Ommatius, Wiedemann, 1821

Scarbrough, Aubrey G., 2008, New Ommatius Wiedemann from the Americas with two new species groups, keys, and taxonomic notes (Diptera: Asilidae), Insecta Mundi 2008 (32), pp. 1-14 : 2-3

Key to Ommatius species groups in the Americas

1. Scutellum usually with stout marginal bristles ......................................................................... 2

— Scutellum usually without stout marginal bristles, if present then thin .................................. 6

2(1). Stout anepimeral bristle present ................................................................................................. 3

— Stout anepimeral bristle absent, sometimes long setae or slightly bristly setae present ........... 4

3(2). Hind femora of male with basal anteroventral bristles usually shorter and thinner than those apically, latter usually increasing in length and thickness toward apex of hind femora .......... .................................................................................................................. holosericeus group

— Hind femora of male with basal anteroventral bristles longer and thicker than those apically, latter usually decreasing in length and thickness toward apex of hind femora ......................... .................................................................................................................... amplicatus group

4(2). Fore femora of male with abundant, small, hooked setae posteriorly; legs with unusually long bristles, at least 2/3 as long as respective tibiae or tarsi; basal tarsomere of hind tarsi swollen, about 1/4 wider than adjacent tarsomere; 2-3 sternites with unusually modified vestiture, often forming dense clusters of long dense setae or abundant bristles, bristles often erect single or fused, pencil-shaped with uniform diameters or angular, apices pointed, blunt, clubbed, or flat; sternite 8 of female much longer than wide, apical margin with narrow fissure medially; anepimeron setae sometimes bristly ............................................................. lucidatus group

— Leg and abdominal characters of male normal, not forming dense patterns or enlarged structures as listed above, bristles and setae round in cross-section with acuminate apices, former usually sparse, a few present laterally, in apical corners, or along apical margin; sternite 8 of female wider than long, apical margin without fissure medially; anepimeral setae never bristly .... 5

5(4). Hind femora swollen, usually <4.5 times longer than wide in anterior view, row of posteroventral bristles divided into basal and apical groups, separated by wide bare space; epandrium with 2- 3 long bristly setae or bristles laterally; base of m 1 narrow, at most 1/2 as wide as diameter at basal 1/3; distiphallus usually horizontal, only slightly depressed or elevated, and tubular, wide in cross-section apically .................................................................................... normus group

— Hind femora more slender, usually 5-6 times longer than wide in anterior view, row of posteroventral bristles not divided into two groups or separated by wide bare space; epandrium without long bristly setae or bristles laterally (except O. alexanderi Farr and O. spinosus Scarbrough ); base of m 1 wider, usually 2/3-3/4 as wide as diameter at basal 1/3; distiphallus curved or angled ventrally, narrow in cross-section apically ..................................................... costatus group

6(1). Hind femora of male swollen and arched, about 3 times longer than wide medially, anteroventral bristles unusually long, about 1/3 as long as hind femora; posteroventral bristles flat with round apices; hind tibiae clubbed apically; segments 7-8 of female with several unusually long, stout bristles laterally sternite 8 of female strongly produced apically, apical margin with a prominent truncate or acuminate spine medially, transverse band of numerous long and short stout bristles present posteriorly ................................................................ hanebrinki group

— Hind femora and hind tibiae of male slender, neither swollen, arched, or clubbed apically, hind femora> 3 times longer than wide medially, bristles not unusually long, about 1/5 as long as hind femora, round in cross-section and tapered to acuminate apex; segments 7-8 of female without unusually stout bristles laterally; sternite 8 of female not strongly produced, apical margin with shallow W-shaped or U-shaped notch, V-shaped row of 8-10 bristly setae or bristles present posteriorly .................................................................................................................... 7

7(6). Scutellum with thin marginal bristles or setae; anepisternum sometimes with bristly setae; epandrium constricted preapically, dorsal corner abruptly projected dorsally; aedeagus thick apically, apex depressed abruptly, usually without a spine-like ventral spire (except in O. praestigiatus Scarbrough and O. integerrimus Scarbrough ) ......................... pumilus group

— Scutellum without marginal bristles; anepisternum bare, if setae present never bristly; epandrium usually notched dorsoapically, not abruptly angled dorsally; aedeagus thinner apically, styletlike with acuminate apex, and projecting horizontally beyond aedeagal sheath; ventral spire present ............................................................................................................... tibialis group