Dideomima coquilletti (Williston, 1891):19

The single species of this genus bears a superficial resemblance in body shape and colour pattern to Didea but there are few close similarities in structure. It may be related to Asiodidea from the eastern Palaearctic, to which it is very similar in external characters, but the male terminalia of the two genera are very different and the resemblance is possibly due to convergence. The terminalia of Dideomima are among the most aberrant in the tribe. The attachment of the superior lobe to the aedeagal base is found nowhere else, and an aedeagus not divided into a basal portion and an articulated distal portion occurs elsewhere only in Simosyrphus. The extremely short surstylar apodeme and the broad dorsal bridge of sternite 9 are also very unusual features (from Vockeroth 1969).

Vockeroth (1969) described a new genus, Dideomima, for the species coquilletti Williston.

Synonyms:

Didea coquilletti Williston, 1891: 19.

Adapted from Vockeroth (1969).

Large robust species with deep angulate loop in vein R4+5 and a broad flattened abdomen with broad unbroken yellow fasciae.

Head: Eye bare. Face yellow, only slightly pollinose. Tubercle broad but not at all prominent.

Thorax: Scutum shining black with broad, entire, poorly defined, yellow, yellow-poIlinose, lateral margin. Scutellum bright yellow. Pleura black below, mostly obscure yellow and yellow poIlinose above with median third of anepisternum black. Dorsal and ventral katepisternal pile patches narrowly separated posteriorly, otherwise broadly separated. Metasternum bare. Vein R4+5 very deeply dipped into cell R4+5, the lower end of the loop sharply angulate or acutely rounded.

Abdomen oval, broad, flat, strongly margined. Tergum 2 with a pair of large rounded oblique yellow spots; terga 3 and 4 each with a very broad anterior basal yellow fascia which is narrowed laterally and weakly emarginate posteriorly; tergum 5 yellow with a very narrow, slightly arcuate, black fascia. Sterna yellow, 3 and 4 (and 5 in female) usually each with an apical or subapical black fascia.

Male genitalia: Large. Tergite 9 broad, cercal notch shallow, cerci small. Surstylus very broad, rounded apically, thin, shell-like, slightly convex, the apicoventral margin compressed; outer surface with dense, rather short hairs, inner surface with moderately abundant short stiff setae. Surstylar apodeme extremely short, directed mediad and scarcely anteroventrad. Sternite 9 very short dorsally, projecting strongly anteroventrally, posteroventrally with very broad deep emargination which has a small U-shaped notch at lower end; sternite closed posterodorsally by a broad bridge. Superior lobe slender basally, strongly broadened towards apex and subtruncate apically, strongly compressed, slightly thickened only posterodorsally, with many very short hairs on lateral surface and a few slightly longer hairs at apex; the two superior lobes strongly converging apically, each firmly bound by membrane near its apex to base of aedeagus. Aedeagus rather strongly sclerotized throughout, not divisible into basal and articulated distal portions. Aedeagus anteroventrally on each side with a sub circular plate from which projects a long, slender, tapering, strongly curved, acute, hook-like process. Distad to these plates, aedeagus tapers slightly to beyond mid length where it is abruptly expanded laterad and dorsad, is produced anterolaterad into a subacute point on either side, and bears anteriorly a small depressed sub rectangular membranous flap. Apex of aedeagus, not at all membranous. Aedeagal apodeme unusually Iong, expanded, and strongly compressed anteriorly.

Dideomima coquilletti (Williston, 1891).

Williston, S.W. (1891-92) Fam. Syrphidae. Biol-Centr.-Am. Ins., Dipt. 3: 1-56 [1891.12.??]; 57-72 [1892.02.??]; 73-78 [1892.05.??], pl. 1, 2, figs. 1-12.

Body length: 10.4 to 12.2 mm (Vockeroth 1969).

Dideomima coquilletti is a New World specie sknown from Arizona, and from Mexico To Guatamala.