Agapetus, Curtis, 1834

Etnier, David A., Parker, Charles R., John T. Baxter, Jr., Long, Todd M. & Drive, News Sentinel, 2010, A review of the genus Agapetus Curtis (Trichoptera: Glossosomatidae) in eastern and central North America, with description of 12 new species, Insecta Mundi 2010 (149), pp. 1-77 : 47-50

Key to Agapetus males of eastern and central North America.

(Males are unknown for A. aphallus .)

1. Segment X ( Fig. 13a), shaped like head of an ibis, beak pointing downward; inferior appendage shaped like a banana, extending posteriorly approximately half its length beyond the end of segment X .................................... Agapetus ibis Etnier, Baxter, and Parker n. sp., p. 21

— Segment X not like an ibis; inferior appendage not banana-shaped, shorter than length of X or extending only slightly posteriad of X ...................................................................................... 2

2(1). Inferior appendage with length at least 4.5 times maximum depth ( Fig. 5, 8, 15, 16, 22) ........ 3

— Inferior appendage with length at most 4 times maximum depth ( Fig. 17, 18) ......................... 7

3(2). Each inferior appendage (ventral view) with 2 denticles on inner face, no terminal denticle ( Fig. 5c, 16c) ...................................................................................................................................... 4

— Each inferior appendage (ventral view) with 3 denticles on inner face, one of which is terminal ( Fig. 8c, 15c, 22c) ...................................................................................................................... 5

4(3). Denticle near middle of inferior appendage (ventral view) in middle of narrow triangular shelf ( Fig. 5c); preanal appendage ( Fig. 5b) typically curved in dorsal view (concave outer margin) ............................................... Agapetus baueri Etnier, Parker, and Baxter n. sp., p. 10 — Denticle near middle of inferior appendage at posterior end of broad, serrate, trapezoidal shelf ( Fig. 16c); preanal appendage nearly straight in dorsal view ( Fig. 16a) .................................... ............................................................................................. Agapetus jocassee Morse , p. 25

5(3). Inferior appendages markedly sinuate on outer margin, denticles approximately evenly spaced along inner margin ( Fig. 8c) .... Agapetus flinti Parker, Etnier, and Baxter n. sp., p. 14

— Inferior appendages with outer margins nearly straight or with apex curved, denticles unequally spaced on inner margin ( Figs 15c, 22c) .................................................................................... 6

6(5). Inferior appendages ( Fig. 22c) with proximal denticles close together, one slightly posterior and dorsal to the other; terminal denticle not darkly pigmented. Agapetus pinatus Ross , p. 35

— Inferior appendages ( Fig. 15c) with proximal denticles rather widely spaced and all denticles darkly pigmented ........................................................................ Agapetus iridis Ross , p. 24

7(2). Posterior portion of segment X truncate and vertical or nearly so, and with 3-15 large denticles or spines directed posteriad or dorsad ( Fig. 1, 14, 20, 23, 27) ...................................................... 8

— Posterior margin of segment X may have small serrae, but never with more than 2 large denticles or spines ( Fig. 4, 24), or if so X is definitely not truncate ...................................................... 12

8(7). Ten to fifteen denticles on posterior margin of X, similar in size, orientation, and spacing ( Fig. 14, 20, 23) ....................................................................................................................................... 9

— Nine or fewer denticles on posterior margin of X, irregular in size, orientation, and spacing ( Fig. 1, 27) ....................................................................................................................................... 11

9(8). Denticles on posterior margin of X do not extend above dorsal margin of X ( Fig. 14); inferior appendage ( Fig. 14c) with two denticles connected by a darkened ridge .................................... ..................................................................................................... Agapetus illini Ross , p. 23

— Denticles on posterior margin of X extend well above dorsum of X ( Fig. 20, 23); inferior appendage ( Fig. 20c, 23c) with two denticles, not connected by darkened ridge ..................................... 10

10(9). Dorsal setae of preanal appendage normal, not nearly as thick as denticles on posterior margin of X ( Fig. 20a); distal denticle of inferior appendage ( Fig. 20c) on ventral margin; denticulate posterior arms of X not flexible and with denticles in a double row ........................................... ............................................................................................ Agapetus minutus Sibley , p. 31

— Dorsal setae of preanal appendage as thick as denticles on posterior arms of X ( Fig. 23a); distal denticle of inferior appendage ( Fig. 23c) submarginal; denticulate posterior arms of X flexible and with denticles in a single row ............................................................................................... ............................................... Agapetus ruiteri Parker, Etnier, and Baxter n. sp., p. 36

11(8). Posterior margin of X with 4-9 denticles; ventral margin of X curved ventrad on distal 1/4 ( Fig. 1a) ................................................................................. Agapetus alabamensis Harris , p. 4

— Posterior margin of X with only 3 denticles; ventral margin of X horizontal or curved dorsad on its distal 1/4 ( Fig. 27a) ....... Agapetus tricornutus Etnier, Parker, and Baxter n. sp., p. 42

12(8). No denticles associated with segment X ( Fig. 3); known only from Missouri ............................... ................................................................................................... Agapetus artesus Ross , p. 7

— Denticles present on segment X ................................................................................................ 13

13(12). Inferior appendage with finger-like dorsal projection ( Fig. 9a) ... Agapetus gelbae Ross , p. 16

— Inferior appendage not finger-like ( Fig. 4a, 7a, 9a, 12a, 18a, 21a, 28a) ................................... 14

14(13). Greatest depth of inferior appendage at or beyond mid-length, not strongly tapered posteriad ( Fig. 4a, 7a, 9a, 12a, 18a, 28a) ........................................................................................................ 15

— Inferior appendage with greatest depth near base, strongly tapered ( Fig. 21) ......................... 27 15(14). Inferior appendage with greatest depth near posterior end, not rhomboid ( Fig. 12, 24, 26) .... 16

— Inferior appendage not as above; if slightly deeper near posterior end the appendage is rhomboid ( Fig. 6a) .................................................................................................................................. 20

16(15). Tip of inferior appendage concave to truncate ( Fig. 26a), or deeply incised ( Fig. 10a) ............. 17

— Tip of inferior appendage slightly produced near mid-depth ( Fig. 12, 24) ................................ 18

17(16). X with prominent rounded lobe apicoventrally; end of inferior appendage concave, occasionally nearly truncate ( Fig. 26a) ......................................................... Agapetus tomus Ross , p. 41

— X with narrow acute projection apicoventrally; end of inferior appendage deeply incised ( Fig 10a) .............................................. Agapetus harrisi Etnier, Parker, and Baxter n. sp., p. 17

18(16). Tip of inferior appendage concave both above and below median protrusion ( Fig. 12); each inferior appendage with two terminal denticles ......... Agapetus hessi Leonard and Leonard , p. 20

— Tip of interior appendage convex below median protuberance ( Fig. 24, 29); each inferior appendage with a single terminal denticle............................................................................................... 19

19(18). Tip of each ventral arm of X with one (rarely two) denticles ( Fig. 29a); base of X with a laterally directed triangular denticle on each side ( Fig. 29c) .................................................................... .................................................................... Agapetus walkeri (Betten and Mosely) , p. 46

— Tip of each ventral arm of X with a cluster of about 5 denticles ( Fig. 24a); denticles typically absent near base of X ( Fig. 24c) ........................ Agapetus spinosus Etnier and Way , p. 38

20(15). Inferior appendage strongly rhomboid ( Fig. 6a, 7a, 11a, 17a) .................................................. 21

— Inferior appendage with tip rounded ( Fig. 4a, 28a), or truncate ( Fig. 18a) .............................. 24

21(20). Inferior appendage nearly a perfect rhombus (anterior, posterior, dorsal, and ventral margins subequal, Fig. 6a, 7a) ............................................................................................................. 22

— Inferior appendage with dorsal and ventral margins at least 1.5 times longer than anterior and posterior margins ( Fig. 11, 17) ............................................................................................... 23

22(21). Segment X with terminal denticle curved upward at posterioventral corner ( Fig 6a) .................. ............................................................................................... Agapetus crasmus Ross , p. 12

— Segment X with blunt tooth at posterioventral corner, then posterior margin straight and sloping anteriad ( Fig. 7) ........................................................ Agapetus diacanthus Edwards , p. 13

23(21). Segment X (lateral) terminates in a darkened, long denticle, with a shorter, less darkened denticle above it ( Fig. 11a) .............. Agapetus hesperus Etnier, Baxter, and Parker n. sp., p. 18

— Segment X (lateral) terminates in a single denticle ( Fig. 17a) ...................................................... .......................................... Agapetus kirchneri Parker, Etnier, and Baxter n. sp., p. 27

24(20). Inferior appendage smoothly and rather symmetrically rounded at tip ( Fig. 4a, 19a, 28a)..... 25

— Inferior appendage with tip obliquely truncate, sloping down and back from posteriodorsal corner ( Fig. 18), known only from Arkansas .................................... Agapetus medicus Ross , p. 29

25(24). Segment X ( Fig. 28a) with posterior margin truncate, nearly vertical ......................................... ..................................................................................................... Agapetus vireo Ross , p. 44

— Segment X ( Fig. 4a. 19a) sloping down and back ...................................................................... 26

26(25). Segment X ( Fig 19a) with posteriodorsal corner present; X terminating ventrally in a pointed projection ventral to ventral margin ........................................................................................... .................................... Agapetus meridionalis Etnier, Parker, and Baxter n. sp., p. 30

— Segment X ( Fig. 4a) lacking posteriodorsal corner; X terminating ventrally in a pointed projection level with ventral margin..................................................... Agapetus avitus Edwards , p. 8

27(14). Tip of X with 2 sharp denticles, each with length subequal to depth of preanal appendage ( Fig. 25) ............................................... Agapetus stylifer Etnier, Baxter and Parker n. sp., p. 39

— Tip of X with 2 short, blunt protuberances ( Fig. 21) ...................................................................... .............................................. Agapetus pegram Etnier, Baxter and Parker n. sp., p. 33