Key to species of the Oncometopia orbona group

(females of O. unispina sp. n. are unknown)

1 Males............................................................................................... 2

- Females............................................................................................. 8

2 Ventral surface of aedeagal shaft with bulging subapical expansion bearing spinelike process (Fig. 2 B, C).... O. orbona (F.)

- Ventral surface of aedeagal shaft without bulging expansion, subapical spinelike process attached to shaft directly or via mem- branous stalk.......................................................................................... 3

3 Aedeagus in lateral view approximately as long as tall; dorsal margin of base long, broadly concave on transition between atrium and shaft; shaft in caudal view expanded in basal half, uniformly narrow in apical half......................... 13

- Aedeagus in lateral view taller than long; dorsal margin of base indistinct or short, without distinct broad concavity on transi- tion to shaft; shaft in caudal view not as above............................................................... 4

4 Aedeagal shaft strongly compressed laterally, in lateral view at least twice as wide as in caudal view (Fig. 9 H, J); lateral margin of subgenital plate concave at midlength (Fig. 9 J).............................................. O. acicularis sp. n.

- Aedeagal shaft at least as wide in caudal as in lateral view; lateral margin of subgenital plate concave proximally of midlength or nearly straight...................................................................................... 5

5 Aedeagal shaft in caudal view expanded in apical portion (Fig. 8 C)................................... O. obtusa (F.)

- Aedeagal shaft in caudal view widest in lower portion or parallel-sided........................................... 6

6 Process of shaft attached near apex of shaft, on short membranous stalk or without stalk (Figs. 6 J, K, N–T).................................................................................................... O. clarior (Walker)

- Process of shaft attached in basal half of shaft, on long membranous stalk (Figs. 10 I, J, 11J, K, 12, E, F)................ 7

7 Process of atrium with short spine (Fig. 12 E, F)................................................ O. unispina sp. n.

- Process of atrium without spine (Figs. 10 I, J, 11J, K)............................... O. lepida sp. n. or O. pelvica sp. n.

8 Sternum VII without median longitudinal carina, with preapical depression; posterior margin with median lobe angularly pro- duced, 1– 2x wider than long (Fig. 9 M). Genital chamber sclerites mushroom-shaped (Fig. 9 K–N)....... O. acicularis sp. n.

- Sternum VII slightly carinate along median line, without preapical depression; posterior margin with median lobe broadly con- vex, 3– 6x wider than long. Genital chamber sclerites different or absent...........................................9

9 Sternum VIII sclerite(s) present......................................................................... 10

- Sternum VIII sclerite(s) absent.......................................................................... 11

10 Vestibulum not produced posteriorly. Sternum VIII sclerites transverse, sculptured with oblique ridges, often merged into sin- gle deltoid sclerite, in dorsal view convex (Fig. 2 H)............................................... O. orbona (F.)

– Vestibulum produced into subrectangular posterior extension. Sternum VIII sclerite unpaired and unsculptured, in dorsal view concave along midline (Fig. 11 R)............................................................. O. pelvica sp. n.

11 Genital chamber sclerites thimble-shaped, converging anteriorly, attached to anterior ends of 1st valvulae (Fig. 10 L, M).............................................................................................. O. lepida sp. n.

- Genital chamber sclerites deltoid, attached to 1st valvulae posteriorly of their anterior ends...........................12

12 Posterior extension of vestibulum pouch-like, extending laterally and posteriorly beyond genital chamber sclerites (Fig. 7 B, E, N). Genital chamber sclerites attached to 1st valvulae anteriorly of articulation with 1st valvifer, their posterior ends not forming loop, dorsolateral margins not undulate (Figs. 7 C, F, G, 8H)......................... O. clarior (Walker) or O. obtusa (F.)

- Posterior extension of vestibulum narrow, delimited by genital chamber sclerites forming its ventrolateral walls. Genital cham- ber sclerites attached to 1st valvulae at the level of articulation with 1st valvifer, posteriorly fused into distinct median loop, their dorsolateral margins undulate (Figs. 3K, 4 O)............................................................... 13

13 Crown, pronotum, and mesonotum with well developed pattern of black markings (Fig. 1 I–P); Florida and South Georgia ....................................................................................... O. nigricans (Walker)

- Without black pattern or with few small poorly distinct markings (Fig. 1 Q–X); southeastern Texas to Veracruz .................................................................................................. O. hamiltoni sp. n.