Eurysphindus LeConte

McHugh, Joseph V. & Kiselyova, Tatiana G., 2003, First Descriptions for Larval Stages of Eurysphindus (Coleoptera: Cucujoidea: Sphindidae), The Coleopterists Bulletin 57 (1), pp. 17-25 : 18-20

Larva of Eurysphindus LeConte

Description. Mature larvae 2.9–3.4 mm. Body ( Figs. 1, 15 ) elongate, fusiform, straight, slightly compressed. Dorsum of thorax and abdomen with narrow transverse bands of weakly sclerotized tergal plates. Integument smooth with some small granules, especially on terga ( Fig. 7 ). Body lightly pigmented, with darker head and a few weakly pigmented posterior abdominal terga. Vestiture consisting of erect setae, most setae on head simple. Most setae on dorsum of thorax and abdomen spiraled at apex and minutely capitate ( Figs. 7 , 15 ).

Head: Protracted and prognathous, moderately broad, slightly flattened, lightly sclerotized. Antenna ( Figs. 5 , 10 ) well-developed, 3-segmented, inserted laterally, anterior to stemmata, arising from large swollen membranous base; antennomere ratio AI:II:III 5 4:13:3; AII broadest at midlength, bearing sensorium apically and AIII subapically, sensorium large, 4/5 length AIII, conical, gradually curved toward AIII; AIII bearing 1 long and 2 short apical setae. Stemmata 6 per side ( Fig. 12 ), arranged in 2 subparallel rows of 3. Epicranial stem short, wide ( Fig. 1); frontal arms lyriform and contiguous at base. Median endocarina absent. Frontoclypeal suture absent ( Fig. 10 ); clypeolabral suture incomplete; labrum free. Mandibles ( Figs. 3, 4, 6 , 11 ) symmetrical to weakly asymmetrical, bidentate, with prominent ventral accessory process; mola well-developed, tuberculate, prostheca narrow, fixed, hyaline, acute at apex, abruptly curved mesad at about 1/3 length. Ventral mouthparts ( Figs. 8, 9 ) retracted. Maxilla with transverse cardo, elongate stipes, well developed articulating area, 3-segmented palp, well developed palpifer; galea and lacinia completely fused to form broad, obtuse mala, malar apex covered with moderately dense, curled setae, mesal margin bearing a single longitudinal row of 8–9 long stout setae and 2 small, straight teeth near apex of mesal margin. Labium free to base of mentum; ligula short and broad; labial palps short, 2-segmented, widely separated. Hypopharynx ( Fig. 8 ) bilobed at apex, with 6 stout setae arranged in a ‘‘V’’ shape in median area; lateral lobes covered with very long, seta-like asperities; hypopharyngeal sclerome a curved transverse bar with median acute projection; epipharynx membranous, with long, seta-like asperities laterally and a transverse row of approximately 25 placoid sensilla near mid-length ( Fig. 2 ). Ventral epicranial ridges absent. Gula absent.

Thorax and Abdomen: Thoracic and abdominal terga I–VIII with paired, weakly sclerotized plates ( Fig. 1); anterior tergites unpigmented, posterior abdominal plates weakly pigmented. Thoracic tergites only weakly projecting laterally. Legs well-developed, 5-segmented; tarsungulus with 2 setae lying one distal to the other ( Fig. 14 ); coxae widely separated. Segments TI–III and AI–VIII each with a membranous, pleural, mound-like projection bearing 8–12 long setae ( Figs. 1, 15 ). Abdominal segments AI–VIII each also bearing a more ventral pleural, mound-like projection ( Fig. 15 ), with 4–5 long setae. Tergum A9 well-developed, simple. Segment A10 short, circular, posteriorly oriented.

Spiracles: small, annular, projecting slightly from body wall ( Fig. 13 ), one pair on mesothorax, 8 abdominal pairs on AI–VIII.

Comments. Eurysphindus differs from all known sphindid larvae by the following combination of characters (see Chiao and McHugh 2000): Urogomphi absent; maxillary palp 3-segmented; labial palp 2-segmented; AX lacking pair of ventral membranous lobes each bearing a single curved, stout seta; Tarsungulus bearing 2 setae; Mandible bidentate; Antennomere II 3.5–4.5 3 length AIII. Larvae of the two North American species may be diagnosed as follows.

Eurysphindus comatulus . Mature larva 3.3–3.4 mm; mandibles symmetrical, preapical tooth smooth- feebly serrate on distal edge, tubercles of mola broad, rounded ( Fig. 6 ); lacinial teeth very small, inconspicuous; integument of nota and terga shiny.

Eurysphindus hirtus . Mature larva 2.9–3.0 mm; head smaller and narrower than in E. comatulus ; antennae proportionally longer, legs longer with more strongly projecting coxae; mandibles slightly asymmetrical, apices acute, somewhat falcate; preapical tooth with blunt denticles on distal edge, 4 denticles on right mandible 3 on left; tubercles on mola oblong, rounded, becoming acute on the ventral proximal margin ( Figs. 3, 4 ); lacinial teeth more prominent; integument of nota and terga opaque.

Material Examined. Eurysphindus comatulus : U.S.A.: New York: Tompkins Co., Brooktondale, ex Mucilago crustacea , 3.VIII.1992, J. V. McHugh (.50 early instar larvae, 13 mature larvae, 10 pupae,.2,000 adults). Eurysphindus hirtus : U.S.A.: Georgia: Clarke Co., Athens, Memorial Park, ex Diachea leucopodia , 15. VI.1998, J. V. McHugh (1 early instar larva, 4 mature larvae, 26 adults). Descriptions and figures of mouthparts are based on a single dissected specimen of E. hirtus and five dissected specimens of E. comatulus . Immature and adult specimens of both Eurysphindus species are deposited in the University of Georgia Collection of Arthropods ( UGCA).

Figures

Figs. 10–15. Eurysphindus comatulus larval anatomy. 10) Head, dorsal; 11) mandible, right, dorsal; 12) stemmata, right side, lateral; 13) AIII spiracle, right, lateral; 14) TII tarsungulus, right, anterior; 15) final instar larva, habitus, right side, lateral.

Figs. 2–7. Eurysphindus larval anatomy. 2) E. comatulus, labrum, ventral; 3–4) E. hirtus, mandible, ventral; 3) right; 4) left; 5–6) E. comatulus; 5) antenna, left, ventral; 6) mandible, left, ventral; 7) E. hirtus, TII notum, right side, dorsal.

Figs. 8–9. Eurysphindus comatulus larval maxillolabial complex. 7) Dorsal; 8) ventral.