Megischus niger Smith

Aguiar, Alexandre P., 2006, The Stephanidae (Hymenoptera) of Mexico, with description of six new species and key to western Foenatopus Smith, Zootaxa 1186, pp. 1-56 : 43-52

Megischus niger Smith

( Figs 9–16 , 73–77 )

Megischus niger Smith, 1864a: 44 . Holotype ♀ BMNH (examined); Cameron, 1887: 420; Gauld, 1995: 184. Aguiar, 2004b: 59.

Stephanus niger (Smith) nec Nees, 1812: Schletterer, 1889a: 88, 135; Dalla Torre, 1902: 8; Enderlein, 1905: 475; Kieffer, 1908: 4; Elliott, 1922: 717, 733; Orfila, 1951a: 273.

Description

FEMALE. Holotype specimen. Body length 20.6 mm. Head: Frons arcuately and concentrically ondulate­strigate, approximately in zig­zag pattern; a few transversal strigations ventrally, from eye to eye; mostly covered with few scattered short hairs, which are decumbent upwards; much more abundant pilosity ventrally, decumbent toward clypeus. Coronal area more or less irregularly rugose, sculpture as strong as that on frons. Vertex with three distinct sculpture patterns: anteriorly arcuately carinae; laterally mixing areolate­rugose and irregularly rugose; centrally and posteriorly transversally rugose, becoming fine and very fine as it progresses towards occipital carina, which it reaches only centrally; central impression absent; temple broadly polished; vertex with a few short hairs decumbent forwardly and associated with areolation; gena ventrally with scattered medium size hairs. Occipital carina narrow, width uniform, slightly reflexed towards head surface, dorsally somewhat emarginated; ending very near hypostomal carina; a row of long hairs along its length. Hypostomal area near hypostomal carina with small patch of short hairs. Gena polished, laterally not prominent.

Mesosoma: Prosternum with deep pre­apical depression, alutaceous inside and nearby, otherwise with sparse foveolae, each bearing a medium size erect hair, space in between foveolae polished or faintly alutaceous. Pronotum: colo apically with one strong carina projecting laterally on each side, and one very short, oblique, strong carina in front of it; centrally deeply constricted ( bicolor group), the constriction widely polished (as in Fig. 73 ). Pre­ and semiannular only partially transversely rugose, laterally and dorso­laterally mostly polished. Ventral area on apical 0.2 distinctly alutaceous, the following 0.3 transversely carinate, posterior half polished or faintly longitudinally rugose (similar to Fig. 77 ); pronotum also with sparse foveolation, more concentrated on areas with rugosity; each foveola bearing one long erect hair. Femoral impression best defined by the dorsal rim of ventral area, not clearly differentiated as a channel. Mesoscutum median sulcus and notaulus indistinct or confluent with overall foveolation; lateral lobes with transversal rugosities. Axilla mesally and posteriorly with a few well defined, subcircular foveolae, otherwise polished. Scutellum laterally and posteriorly with some well defined subcircular foveolae; centrally and in between foveolae polished; apex alutaceous, with a few longitudinal microsulci. Mesopleuron with sparse, small foveolae, sparse longitudinal pilosity (as in Fig. 74 ), and antero­ventral patch of short dense pilosity (as in Fig. 78 ); the same dense, short pilosity also present on dorsal part of mesopleuron. Mesopseudosternum polished, discrimen a straight line, not crenulate. Propodeum taken by large, circular, well defined foveolae, which are polished inside; space in between foveolae alutaceous; foveolae more frequent centrally; fusing with transversal rugosities posteriorly, which connect both parapetiolar fovea, making them difficult to distinguish; a small raised area behind the spiracle, with some eight closely spaced foveolae, almost no area left in between them (same overall structure as shown in Fig. 42 ). Spiracular groove well developed, deep, ending near, or at crenulate sulcus; usually with some rugulosities between its apex and crenulate sulcus; its surface irregular (similar to Fig. 42 ). Spiracular carina narrow near spiracle, becoming wider anteriorly; dorsally flat, thus generating a small area, which contains several microfoveolae. Metapleuron dorsally broadly polished, centrally coarsely areolate­rugose, this same pattern of sculpture extending also apically, almost reaching pleuropropodeal fovea; a long hair arising from each areola, plus dense short pilosity in between, extending to dorsal part of metapleuron and reaching its posterior margin; metapleuron ventrally polished; post­foveolar area with arched carinae, at least posteriorly; interfoveolar area polished. Hind coxa transversely rugose or transversely strigate, weakest ventrally; mesal side antero­ventrally with a longitudinal patch of dense hairs; also with long pilosity, as dense as in metapleuron. Hind femur densely and finely alutaceous, matte, also with long, sparse, stiff pilosity, inclined posteriorly at about 45 degrees. Hind tibia alutaceous as in hind femur, strongly pinched on basal 0.4–0.5, but without a posterior longitudinal carina or edge; compressed portion ventrally with conspicuous, sharp edge, ending as soon as dilated portion begins. Hind basitarsomere 3.75 as long as maximum width (lateral view similar to Fig. 76 ). Hind wing with spectral indication of two longitudinal and one transversal vein.

Metasoma: Petiole densely transversely strigate. T3–4 considerably elongate (as in Fig. 75 ), T3–8 densely finely alutaceous; T9 strongly alutaceous. Pygidial sulcus Vshaped, but basally round instead of acute.

Color. Dark brown with yellowish spot on malar space. Metasoma more pale than overall body color; pronotum and legs with reddish tone, more intense on trochanters. Ovipositor sheath subapical white band nearly three times length of dark apex. Wing veins brown, costal cell amber; rest of wing membrane clear or very slightly yellow infuscate. Hind basitarsomere with darker reddish tint than rest of body.

Morphological variation in females. Range of biometric values in Table 1 is specific for Mexican specimens, and excludes values for the holotype specimen, from Panama. Two ratios for the holotype specimen show values beyond the range observed for Mexican specimens: Ov/TT 1.28 and Ov/Hdl 16.23. Other important variations for M. niger in Mexico can be described as follows. Pilosity of hypostomal bridge very variable, from very weak to dense, but always present; semiannular laterally sometimes (20%) transversely strigate; mesopleuron ventro­longitudinal patch of short pilosity sometimes (25%) absent, but hairs may be lost in old museum specimens, in which case the presence of a hair patch is indicated only by weak micropunctures, originally associated with the hairs. Fore wing crossvein 2r between 0.45–0.99 length of vein 4Rs, but most commonly between 0.5–0.7; typical, Central American specimens of M. niger , however, have this ratio mostly around 0.8. The hind basitarsus of Mexican M. niger is generally shorter than in typical specimens of this species, from Central America ; in Mexican specimens, the hind basitarsus maximum length ranges from 2.58–3.55 its maximum width; in specimens from Panama, the type locality, and Costa Rica, these values most commonly fall between 3.6–4.1, although with total measured variation of 3.40–4.15. Forms with body nearly entirely deep black are the most common on the type locality ( Panama) and in other localities in Central America ; these forms also occur in Mexico, but the most common are dark brown specimens with flagellomeres 1–7, fore and mid legs, hind tarsus or at least hind basitarsomere, and sometimes petiole basally or entirely, and parts of remaining tergites, reddish brown (approximately from 114,017,017 to 140,050,050).

MALE. The single Mexican specimen examined is very similar to the female, including its body length, of 19.5 mm. It differs only in having the overall body color generally lighter than the deep black of females; in particular, male legs and metasoma tend to be brown, and the head and pronotum have a weak reddish tone.

Comments

The present species also occurs in Central and South America (unpublished data), from where 21 other Megischus species have been described ( Aguiar, 2004b). Most type specimens of these species were studied, and seem sufficiently distinct from M. niger ; for other species, published descriptions clearly indicate that they also are incompatible with M. niger .

Typical specimens of M. niger are most similar to those found in Panama and Costa Rica, showing the body mostly deep black; semiannular laterally mostly polished ( Figs 74, 77, 78 ); mesopleuron with weak sculpture and polished spaces ( Figs 74, 78 ), anteroventrally bearing a distinct, oblique patch of short white pilosity ( Fig. 78 ); an more elongate hind basitarsus (btl/ w 1.79 –2.50 but often between 3.5–4.5; Figs 14 , 76 ) and T3–4 (T4l/ w 1.41 –1.66, Figs 16 , 75 ) than observed in M. bicolor (btl/ w 1.34 –2.11, Figs 14 , 37 ; T 4l / w 0.64 –1.36, Figs 16 , 40 ). Typical forms of both species also occur in Mexico, but intermediate specimens make nearly a morphological continuum. Recognition of both these species in Mexico is, therefore, more difficult than for specimens from any other location in the Americas. The features cited in the key to species are fairly reliable to separate most specimens of these two species, although some may present problems, particularly some male specimens.

Also similar to the North American M. brevicaudatus Aguiar , but this species has a distinctly shorter ovipositor, with Ov/TT 0.80–0.99 (vs. 1.01–1.27 for Mexican M. niger ); fore and mid legs (except black femora) and hind tarsi reddish; semiannular strongly transversely strigose/rugose; ventral half of gena with punctures, or at least micropunctures; and mesopleuron anteriorly with sparse long pilosity only, without patch of short hairs, also densely or very densely foveolate.

Distribution Originally described from Panama; also known from Guatemala ( Aguiar, 2004b). Here registered for the first time in Mexico.

Material examined (new records)

Seven females, 1 male. 2 ♀♀ EMEC “ Mexico, Portugal, 7 mi. S.E. Simojovel, Chiapas, VII­17­58, J.A. Chemsak. OSUC21226 , OSUC21225 .” ♀ CASC “ Mexico, Chiapas, Municipio Angel Albíno Corzo, along Rio Custepec, below Finca Gadow , alt. 853m, 12­IX­76, D.E. & J.A. Breedlove. Cal. Acad. Sci. Coll. OSUC22864 .” ♀ CASC “ Mexico, Municipio Angel Albino Corzo, along Rio Custepec, below Finca Gadow , alt. 853m, 12­IX­76, D.E. & J.A. Breedlove. OSUC22865 .” ♀ EMEC “ Mexico, Chiapas, Simojovel , VII/18­31/58. OSUC22862 .” ♀ EMEC “ Mexico, Portugal, 7 mi. S.E. Simojovel, Chiapas, VII­17­58, J.A. Chemsak. OSUC22861 .” ♀ FSCA “ Mexico, Quintana Roo, 6 Km S. Playa del Carmen , 17­VI­1991, F.W. Skillman Jr., UV light. OSUC22863 .” ♂ FSCA “ Mexico, Yucatan, 2 Km E Chitzen Itza , 16­VI­1990, M.C. Thomas. OSUC21230 .”

Megischus peninsularis Aguiar , sp. n.

( Figs 9–16 , 79–86 )

Etymology Latin peninsula, same meaning as the identical corresponding English word; in reference to the restricted occurrence of the species in the peninsula of Baja California.

Description

Female. Holotype specimen ( Figs 79–86 ). Body length 27.0 mm. Head: Antenna with 38 flagellomeres; f1–2 tall and laterally flattened, other flagellomeres progressively changing from 9.0 (f4) to 2.3 (f33) times longer than wide. Frons entirely, strongly, from basally transversely to dorsally obliquely areolate­rugose; surface inside areolation polished; with fine, scattered hairs, decumbent towards center or downwards; along eye margins with line of numerous short hairs obliquely decumbent towards clypeus. Coronal area with oval, irregular carinae encircling central ocellum, and several strong, short carinae radially extending laterally and posteriorly from oval carina towards margin of coronal area. Vertex ( Fig. 79 ) apparently glabrous, but with one tiny, delicate hair inside each areola; two distinct sculpture patterns: anteriorly with 5–6 arched, concentric, progressively smaller carinae, continued centro­longitudinally by short, transverse, strong rugosity, almost reaching posterior margin; laterally widely taken by dense and coarse areolation, which changes postero­laterally to foveolation, with some scattered foveolae spreading onto temple ( Fig. 81 ); sculpture aggressively reaching occipital carina dorsocentrally ( Fig. 79 ); central impression absent; temple surface between foveolae polished; gena in dorsal view ( Fig. 79 ) not prominent, but large and round; head at level of gena in dorsal view slightly wider than at eye level (ratio = 1.02); gena ventral half ( Fig. 80 ) densely and coarsely areolate. Occipital carina ( Figs 79–81 ) somewhat sunken into head, narrow, width uniform; fully transversely coarsely rugose, the rugae spaced at about 1–2 times their length; also somewhat reflected towards head surface; ventrally surpassing base of hypostomal carina ( Fig. 81 ), then curving towards its side, ending as a short irregular rugosity. Hypostomal area polished.

Mesosoma: Prosternum with faint pre­apical depression; changing from anteriorly densely and coarsely rugose­foveolate ( Fig. 81 ) to posteriorly foveolate, surface between foveolae polished. Pronotum: colo with 3 pairs of stout carinae, the 2 nd pair largest, almost meeting dorsally, the 3 rd pair very near to, and dorsally curving towards, pronotal fold. Pronotal fold low, similar to a carina, dorso­centrally widely open, the (usually) internal vertical carina exposed. Preannular crossed by a few strong, sharp, transverse carinae. Femoral impression well defined, semicircular in transverse section, width approximately uniform, surface weakly irregular, polished; ventral area anteriorly strongly transversely carinate, progressively changing to posteriorly strongly longitudinally rugose. Semiannular posterior margin, particularly laterally ( Fig. 82 ), with a few stout longitudinal rugosities; otherwise entirely deeply and densely foveolate, the foveolae contiguous or nearly so, mostly polished in between. Mesoscutum anterior portion alutaceous, main area coarsely transversely rugose­areolate, median sulcus and notaulus defined by a series of aligned, deep foveolae. Axilla mesal half taken by deep, coalescent foveolae, anterior half mostly polished. Scutellum ( Fig. 83 ) mostly faintly alutaceous, marginally with widely scattered, well defined, deep, circular foveolae; its lateral area taken by deep, straight crenulation. Mesopleuron ( Fig. 82 ) dorso­anteriorly rugose­areolate, changing to dorsoposteriorly polished, and then to ventral 0.6 densely coarsely foveolate, the foveolae contiguous or almost so, each one bearing one moderately long, delicate hair, so the suface is mostly glabrous; the narrow surface in between foveolae polished. Mesopseudosternum mostly taken by mesopleural sculpture ( Fig. 82 ), except narrowly along discrimen, which is fully deeply crenulate. Propodeum ( Figs 85, 86 ) fully taken by very dense, coarse, complex sculpuring: centrally transversely areolate­rugose, changing to laterally densely foveolate, with numerous microfoveolae on the space in between foveolae; the central pattern changing posteriorly, including on area between spiracle and parapetiolar fovae, to approximately closely areolate, also posteriorly originating about 3 transverse, irregular, parallel rugosities along petiolar foramen; parapetiolar fovea taken by coarse transverse carinae; the foveolae and areolation polished inside. Spiracular groove ( Figs 85, 86 ) more or less distinct, taken by macrosculpture from propodeum; spiracular carina strong, welldelimited; both carina and groove ending at crenulate sulcus ( Fig. 86 ); area lateral to spiracular carina broadly polished ( Fig. 86 ). Metapleuron centrally ( Fig. 86 , in part) coarsely areolate­rugose, with sparse, long, weak hairs associated with areolae, therefore mostly glabrous; ventrally, including post­foveolar area and pleuropropodeal fovea, polished ( Fig. 84 ); interfoveolar area entirely deeply crenulate ( Fig. 82 ). Hind coxa laterally and dorsally from basally foveolate and areolate to apically transversely rugose; ventrally with the same pattern, but much weaker than laterally; mesally not visible; with sparse, delicate, long hairs, decumbent towards apex. Hind femur dorso­apical surface slightly but perceptibly irregular and somehwhat alutaceous; otherwise polished; central tooth longer than apical tooth. Hind tibia compressed portion polished; dilated portion finely alutaceous; femur and tibia covered with long, sparse pilosity, decumbent towards apex; hind tibia posteriorly strongly pinched at basal 0.43, generating a posterior carina or edge and a central, large, somewhat circular, transverse compression; basal half ventrally with a sharp edge, ending where the dilated portion begins (generally similar to Figs 55, 56 ).

Metasoma: Petiole, including ventral side, densely, weakly, transversely strigate. T3 (2 nd metasomal) polished, its surface weakly transversely ondulate; T3–8 very finely alutaceous; T8–9 alutaceous more distinctly than on previous tergites. Pygidial sulcus Ushaped, with a shallow depression on T9, at the base of the “U;” pygidium narrow, fully polished, its apical half reflexed upwards at about 40 degrees, centrally with strong crease, also isolated from basal half by a series of aligned, long hairs.

Color. Body black or deep dark brown, except as follows. Gena on its central, most prominent area, reddish brown (119,045,036); malar space taken by large brownish yellow spot (160,120,040); antenna beyond pedicell and pronotum posterior margin, including all of pronotal lobe, widely caramel­colored (166,091,036); all tarsi, except hind t1 basally dark brown, basal 0.1 of mid femur, scutellum and metanotum posterior margin, propodeum near petiolar foramen, anterior plate of propodeal spiracle, basal and apical ends of petiole, and most of T3–5 orange brown or red brown. Wing membrane fully amber (184,170,114), veins dark brown. Ovipositor sheath externally black with weak violaceous reflections; its lumen pale yellow.

Morphological variation in females. Range of biometric values in Table 1. The paratype is essentially very similar to the holotype, the most important differences listed as follows. Prosternum uniformly areolate/foveolate; colo of pronotum with second pair of carinae continuous, although narrowest at point where they met; the (normally) internal vertical carina exposed as a round lump; propodeum sculpture less complex, entirely areolate/foveolate. Almost entirely black, with weak reddish hue on antenna, head, tarsi and propodeum only.

MALE. Unknown.

Comments

This species is somewhat intermediate between M. brunneus Cresson and M. arizonicus Townes , but is clearly closely related and most similar to M. arizonicus , from which it can be isolated by having the vertex laterally extensively areolate/foveolate ( Fig. 79 ), with some foveolae extending to temple ( Fig. 80 ) (vs. moderately areolate, Fig. 26 , temple polished, Fig. 27 ); interocellar carinae numerous and uniformly arranged ( Fig. 79 ) (vs. few and less well defined, laterally blending with areolation, Fig. 26 ); gena and mesopleuron densely and coarsely foveolate ( Figs 81, 82 ), as in M. brunneus Cresson (vs. gena, Fig. 28 , and mesopleuron, Fig. 33 , weakly or sparsely foveolate); scutellum laterally widely taken by deep, straight crenulation ( Fig. 83 ) (vs. with a narrow submarginal groove, Fig. 31 ); fore and mid coxae coarsely foveolate (as in Fig. 84 ) (vs. mostly polished, Fig. 32 ); and petiole somewhat shorter, 4.77–5.29 longer than maximum dorsal width (vs. 5.04–6.07 on Mexican specimens of M. arizonicus ). Fore wing vein 1M straight at point of connexion with vein 1Cu (vs. somewhat arched, generating a more blunt angle), and crossvein 1cu­a meeting 1Cu nearly opposite point of conexion of 1M/1Cu (vs. weakly but distinctly beyond that point). The stability of the last two features need confirmation, since few specimens were examined, and venation in stephanids may vary even between right and left wings of a same specimen.

Distribution Mexico, apparently restricted to southern Baja California.

Material examined

Two females. Holotype ♀ EMEC “ Mexico, Baja California Sur, La Burrera, 12 air mi. ENE Todos Santos , 1700’, XII­11­1979, J. Doyen Collector. OSUC22876 [barcode, plastic].” Left antenna flagellar section between f12–38 broken, glued to label; apical margin of all wings somewhat damaged, but not compromising veins; left ovipositor sheath broken, glued to label; specimen otherwise complete, clean, well preserved. Paratype ♀ UCRC “ Mexico, Baja La Burrera nr. Todos Santos, 15­XI­81, G. Gordh. OSUC22875.” Fore and hind wings glued to each other, the right pair also glued to body; tip of ovipositor sheaths missing; otherwise complete; unclean but well preserved.

Megischus texanus Cresson

( Figs 9–16 , 96–102 )

Megischus texanus Cresson, 1872: 190 . Holotype ♀ ANSP; Cresson, 1916: 64; Elliott, 1922: 761; Townes, 1949: 364–5; Townes, 1951: 90; Carlson, 1979: 741; Halstead, 1986: 103; Gauld, 1995: 184; Aguiar & Johnson, 2003: 470, 475, 479, 481; Aguiar, 2004b: 63.

Stephanus texanus: Dalla Torre, 1902: 9 ; Elliott, 1922: 716, 730.

Stephanus (Hemistephanus) texanus: Roman, 1917: 14 .

Hemistephanus texanus: Elliott, 1922: 755 .

Morphological variation (males and females)

Female body length for Mexican specimens between 9.6–17.2 mm; range of biometric ratios in Table 1. Male body length between 8.4–9.9 mm. Mexican specimens of the present species display, as a whole, a wide range of morphological variation for delicate features, but also show intense variation on color and, notably, on the sculpture of the pronotum and propodeum. The most pronounced variations can be summarized as follows. Vertex sculpture from entirely delicate, sometimes posteriorly almost fading, to coarse, and then from regularly transverse to mostly irregular; pronotum from almost entirely finely microareolate to mostly strongly transversely carinate; propodeum from predominantly microareolate to widely foveolate/areolate, near petiolar foramen with transverse carinae (most specimens) or longitudinal rugosity, sometimes centrolongitudinally transversely strigate; mesopleuron from mostly microareolate and bearing tiny, delicate foveolae (most specimens) to coarsely and densely foveolate. Color generally varying from body predominantly brown (127,064,000) ( Fig. 101 ) to orange brown (189,124,039) ( Fig. 99 ), rarely bright pale yellow (251,217,008) ( Fig. 97 ); some specimens have the alinotum much darker than remaider of thorax and/or apical segments of metasoma dark brown ( Fig. 99 ). Ovipositor sheath always with a subapical whitish or pale yellow band, but varying from tricolored, with basal portion orange brown or nearly so, and apex black (similar to Fig. 95 ), to bicolored, with basal and apical portion dark brown ( Figs 99, 101 ).

One mexican female specimen from Nogales (Sonora, Mexico), as well as one male from the United States (Toiyabe National Forest, Nevada; Fig. 97 ) represent the most extreme light­colored morphs for the species, with the body almost entirely bright pale yellow, except for metasoma with traces of brown; the ocelli are bluish or hyaline; the sculpture is generally smoother than in differently colored specimens. The external morphology is otherwise typical of M. texanus in every detail.

Comments

This species can be recognized by the combination of the following features. Head surface in between general sculpture polished ( Figs 96, 100 ), except temple with some microreticulation; vertex transversely rugose­strigate, this sculpture stronger or coarser on anterior half and often also centro­longitudinally ( Fig. 96 ); the three anterior coronal tubercles forming an angle of about 90 degrees ( Fig. 98 ); maxillary palp as long as height of head; metapleuron centrally with dense tuft of white hairs; hind basitarsomere basally and behind usually with a black or dark­brown dot which may be hidden inside respective tibia, and petiole nearly fully microareolate ( Fig. 102 ).

Mexican specimens of the present species display, as a whole, much morphological variation, sometimes to the point that the proposition of a separate species can be tempting. However, there seems to be not even one, sound unifying feature that can be used to justify a separate specific status, whichever combination of specimens or feature is tried. The ensuing conclusion is that M. texanus is indeed a highly variable species, particularly in Mexico. Distribution in Mexico apparently has little to do with the observed morphological variation, since all morphs occur in all regions, from Baja California to eastern or western, northern or southern extremes of the main land.

If there is more than one species, they apparently cannot be distinguished by external morphology alone. Some of the color morphs have a unique combination of characters, but, when considered individually, none of these features are unique, that is, there are no clear autapomorphies at this point to characterize distinct species. For example, specimen OSUC20483 has the following combination of characters: overall color brown, metasoma apex black; ovipositor sheath with two colors only: dark brown with subapical pale yellow band; hind coxa, femur an basitarus considerably long; hind basitarsus posterior face basally without a brown or dark spot; pronotal colo with a shallow but distinct depression; overal size small. No other M. texanus specimen looks exactly like this, but each of these features can be found, separately, in several other specimens of M. texanus .

Distribution

Previously reported for the continental United States ( Townes, 1949; Aguiar & Johnson, 2003) and northwestern Mexico (Nogales, Sonora) ( Townes, 1949). Here reported for the first time from several other regions in Mexico.

Material examined (new records)

Twelve females, 4 males. MEXICO: ♀ CASC “ Mexico, Sonora, Alamos , 27­II­1963, P.H. Arnaud Jr. OSUC20509 .” ♀ EBCC “ Mexico, Jalisco, Est. Biol. Chamela, Trampa Malaise , 4­5/VII/1993, Wharton y Sharkey. OSUC21196 .” ♀ LACM “ Mexico, Minas Nuevas nr. Alamos , Sonora, Aug. 25, 1959, R. L. Westcott. OSUC20488 .” ♀ ODAC “ Mexico, 16 mi NE San Blas., Nayarit, VII­21­63, R. L. Westcott. OSUC20499 .” ♀ TAMU “ Mexico, Jalisco, Est. Biol. Chamela, Trampa Malaise , 3­9.vii.1993, Wharton, Sharkey. OSUC21197 .” ♀ UAIC “ Mexico, 5 mi. E. Alamos , Sonora, VIII­11­1973, K. Stephan & D. S. Chandler. OSUC20262 .” ♀ WFBM “ Mexico, Baja Calif. Sur, Playa El Coyote, Bahia Concepcion , em. 14­VII­75, R. L. Westcott; [mesquite]. OSUC20511 .” ♀ EMEC “ Mexico, Mazatlan , 5 mi. N Sin, VII/9­15/70, J.A. Chemsak. OSUC20510 .” ♀ CDAE “ Mexico, Baja Calif. Sur, Los Barriles , V/5­6/1979, Malaise Trap 10AM­5 PM, J. Slansky. OSUC20513 .” ♀ SEMC “ Mexico, Tamaulipas, 6.2 mi S San Fernando, 8 June 1966, U. Kans. Mex. Exped. OSUC20506 .” ♀ TAMU “ Mexico, Oaxaca, 11.3 mi. se. Totolapan , July 21, 1974, Clark, Murray, Ashe, Schaffner. OSUC20512 .” ♂ CNCI “ Mexico, 5 mi. S. Monterrey , N. L. Mex., VII­22­1963, H. & A. Howden. OSUC20469 .” ♂ LACM “ Mexico, Michoacan, 9mi. e. Capirio, 800’, 6 July 1970, E. Fisher & P. Sullivan. OSUC20507 .” ♂ TAMU “ Mexico, Nuevo Leon, 9mi. s. Monterrey , 11 Aug. 1972, E.E. Grissel; taken on Parthenium xanthocephalum along road. OSUC20508 .” UNITED STATES: ♀ CNCI “ USA, 15 mi. NE Rio Grande City, Tex. , VI­3­54, H. Howden. OSUC20497 .” ♂ LACM “ USA, Toiyabe Natl. For., Spring Mts. , NEV., Clarck Co., 2­VIII­71, A. E. Lewis. OSUC20496 .”

Figures

FIGURES 9–16. Values of morphometric ratios for all examined female specimens of all species of Mexican Megischus. Species grouped in the Y­axis according to their order of appearance and morphological similarity in the key to species; key structure also indicated by the dendrogram applied to Y­axis of Figure 9. Legends for all graphs: an, M. anaxeus, sp. n.; az, M. arizonicus; bc, M. bicolor; cl, M. celaenocephalus, sp. n.; jc, M. jaliscoensis, sp. n.; ml, M. melanogladius, sp. n.; mx, M. mexicanus, sp. n.; ng, M. niger; pn, M. peninsularis, sp. n.; tx, M. texanus. For ratio abbreviations, see text.

FIGURES 73–78. Megischus niger Smith, ♀. 73, pronotum and anterior part of mesonotum, dorsal; 74, pro­ and mesothorax, left; 75, apex of petiole and tergites 3–4, dorsal; 76, apex of hind left tibia and its respective tarsus, lateral; 77, pronotum and prosternum (detached), left; 78, posterior half of pronotum, mesopleuron, and part of propodeum + metapleuron, left. Illustrations not to scale.

FIGURES 35–42. Megischus bicolor (Westwood), ♀. 35, head, dorsal; 36, pronotum and prosternum, left; 37, apex of hind left tibia and its respective tarsus, lateral; 38, pronotum and anterior part of mesonotum, dorsal; 39, mesopleuron, left; 40, apex of petiole and tergites 3–4, dorsal; 41, intercoxal space between hind coxa, posterior view; 42, propodeum, dorso­lateral, left. Illustrations not to scale.

FIGURES 1–6. General morphology of Stephanidae. 1, head, frontal; 2, head, dorsal; 3, pronotum, dorsal; 4, head, posterior; 5, prothorax, left; 6, propodeum and metapleuron, left. Slightly modified from Aguiar (2001); used with permission.

FIGURES 79–86. Megischus peninsularis, sp. n., holotype ♀. 79, head, dorsal; 80, head, dorsolateral, left; 81, head, latero­ventral, slightly shifted posteriorly to show gena; 82, posterior half of pronotum, mesopleuron, and part of propodeum + metapleuron, left; 83, axilla, scutellum and crenulate sulcus, shifted to the left; 84, post­foveolar area and mid coxa, left; 85, propodeum + metapleuron, dorsal; 86, same, detail of left side. Illustrations not to scale.

FIGURES 51–59. Megischus anaxeus, sp. n., ♀. 51, head, dorsal, holotype; 52, head, lateral but slightly more posterior than anterior, to show gena, holotype; 53, prosternum, ventral, slightly shifted towards left hemisternite, holotype; 54, pronotum and anterior part of mesonotum, dorsal, paratype; 55, hind left tibia, posterior view, paratype; 56, hind left tibia, lateral, paratype; 57, same, detail of central compression; 58, propodeum + dorsal part of metapleuron, to show spiracular groove, left, holotype; 59, interfoveolar and postfoveolar areas, between mesopleuron and metapleuron, holotype. Illustrations not to scale.

FIGURES 26–34. Megischus arizonicus Townes, ♀. 26, head, dorsal; 27, head, dorso­lateral; 28, gena, left; 29, pronotum and anterior part of mesonotum, dorsal; 30, pronotum, anterior half, dorsal; 31, axilla, scutellum and crenulate sulcus, dorsal; 32, mid left coxa; 33, mesopleuron, propodeum (part) and metapleuron (part), left; 34, interfoveolar area, propodeum and metapleuron, left. Illustrations not to scale.

FIGURES 96–102. Megischus texanus Cresson. 96, head, dorsal, ♀; 97, light colored form, habitus, ♂; 98, coronal area and respective anterior ocellum, dorsal, ♀; 99, form with darkened mesonotum and apex of metasoma, full dorsal view, ♀; 100, detail of frons, left, ♀; 101, habitus, ♀; 102, petiole, dorsal, ♀. Illustrations not to scale.

FIGURES 87–95. Megischus mexicanus, sp. n., ♀. 87, head, dorsal, holotype; 88, pronotum + prosternum, left, holotype; 89, pronotum, dorsal; 90, propodeum + metapleuron, dorso­lateral left and slanted forward, holotype; 91, hind left tibia, posterior view, holotype; 92, mesonotum, including scutellum, also part of crenulate sulcus, paratype OSUC22877; 93, crenulate sulcus, interfoveolar area, propodeum + metapleuron, left, holotype; 94, hind left coxa, mesal, paratype OSUC22878; 95, ovipositor and sheaths, lateral, holotype. Illustrations not to scale.