Grallipeza footei (Cresson)

Marshall, S. A., 2013, Grallipeza Rondani (Diptera: Micropezidae: Taeniapterinae) of the Caribbean and North America, Zootaxa 3682 (1), pp. 45-84 : 59-61

Grallipeza footei (Cresson)

Figs. 20–24

Systellapha footei Cresson, 1926:266

Grallipeza footei, Hennig, 1934: 307 ; Steyskal, 1968:48.7 Description: Size: 10–12 mm. Colour: Head, including frontal vitta and palpi, almost entirely orange; ocellar triangle black, lower half of clypeus dark brown, lower face white, gena and central occiput all or partly silvery, anterior margin of orbital strips sometimes darkened. Most of fore femur (all but base in female and a diffuse preapical pale area) and almost all of fore tibia (except apex) brown, fore tarsomeres 1–3 white ( Fig. 20 ) to pale yellow (rarely as dark as Fig. 21 ), tarsomere 3 sometimes light brown distally; tarsomeres 4–5 dark brown. Mid and hind femora orange with a brown apex. Tarsomere one of hind leg white, tarsomeres 2–5 pale brown. Thorax almost entirely orange, postpronotum and sometimes notopleuron darker. Katepisternum with a double row of golden bristles. Female abdomen with tergite 1 pale reddish brown, tergites 2–7 dark reddish brown and densely setulose, oviscape shining dark brown except pale apex, sparsely but distinctly setulose. Abdominal pleuron of female mostly white, dorsal margin black on segments 2–5. Male abdominal syntergite 1–2 light brown, tergites 3– 5 yellowish to brown and densely setulose, posterior corners of tergite 3 very dark, tergite 6 dark and shining bare, epandrium elongate dark brown and entirely densely setulose. Male abdomen with a distinct, large, round, yellowbrown microsetulose membranous dome on pleuron of segment 2, pleuron otherwise white to pale cream yellow.

Head: Arista bare on distal half, basal half with relatively short hairs approximately twice as long as width of basal aristomere. Pedicel with long ventroapical bristles, one almost as long as first flagellomere. Frontal vitta flat, parallel sided except at anterior margin where it joins the lower orbital margin to form a slightly differentiated transverse strip, lower orbital margins distinctly elevated.

Thorax: Cervical sclerite convex and smooth ventrally. Fore femur with only small ventral setulae. Two distinct dorsocentral bristles, 1–2 small suprahumeral bristles. Postpronotum with sparse small setulae, concentrated near anterior margin. Wing: Anal cell entirely setulose. Membrane with dark longitudinal wing infuscation, entirely filling cell R4+5 and much of cell dm, reaching wing apex. Tarsomeres 4 and 5 of fore leg strongly flattened and expanded ( Fig. 21 ).

Male abdomen: Sternite 5 ( Fig. 22 ) with anterior part (base) and posterior part (genital fork) similar in length, base of fork narrowly U-shaped, inner surface of arms bare in basal quarter but with 12–14 spines on distal 3/4, outer surface with sparse hairs. Epandrium small, microsetulose except at base, sparsely and evenly setose, slightly longer than the shining bare sternite 8. Distiphallus unusually long, narrow and ribbon-like, much longer than epandrium and ending in a small swelling (bulb) ( Fig. 23 ).

Female abdomen: Oviscape almost as long as preabdomen (extending to tergite one), four times as long as tergite 6 and almost entirely bare and shining except at apex. Common spermathecal duct uniformly narrow, similar to single duct, narrowing slightly upon splitting into separate short ducts leading to very distinctive paired spermathecae with spherical, striate bodies with an apical depression and a broad, tapered basal stem covered with conspicuous processes ( Fig. 24 ). Single spermatheca distinctly asymmetrical, with one large lobe and one small lobe; distal part of single duct with a short section delineated by strongly constricted areas.

Type material: Holotype 3 ( USNM # 27064) and three paratypes (1 3, 2 Ƥ, USNM): Dominica, Yale Expedition, H. W. Foote.

Other material examined: Dominica. Point Casse. 2miNW. “V.4.1965”, D.R. Davis (1 Ƥ, USNM); Freshwater Lake, vi.9.1965, D.R. Davis (1 Ƥ, USNM); Freshwater Lake, May.23.1966, G. Steyskal (1 Ƥ, USNM); S. Chiltern Est., 2.ii.1965, W.W. Wirth (1 Ƥ, USNM); Clarke Hall Est., v.14.1966, G. Steyskal (1 3, USNM); South Chiltern, 6.ii.1964, H. Robinson (1 3, USNM).

Comments: Grallipeza footei is easily distinguished from the generally smaller, much more common Dominican endemic species G. spinuliger by the dark longitudinal wing infuscation, which entirely fills cell R4+5. Similar wing pigmentation is seen in the apparently closely related G. flavicaudata from Montserrat. The swollen apical tarsomere of the foreleg also distinguishes G. footei from all congeners, and both the male and female terminalia are distinctive.

Figures

FIGURES 20 – 24. Grallipeza footei. 20, female right lateral; 21, male front leg; 22, male sternite 5; 23, male terminalia; 24, spermathecae and ducts.