Agapetus hessi Leonard and Leonard

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 : 20-21

Agapetus hessi Leonard and Leonard

Fig. 12a, 12b, 12c . Map 12

Agapetus hessi Leonard and Leonard 1949: 1

Type locality, South Branch Au Sable River, T 25N, R 2W, S21, Crawford Co., MI. (University of Michigan Museum of Zoology)

Diagnosis. The slender ventral arms of X that diverge distally to a transverse terminal denticle or group of denticles are shared by A. kirchneri , A. spinosus , and A. walkeri . Differs from A. kirchneri in lacking sclerotized posteriodorsal areas of X and a darkened ventral row of denticles on inferior appendages; and in having a lateral, horizontal carina on the inferior appendages. Differs from A. spinosus in having ventral arms of X with a single denticle, occasionally two (five or more denticles in A. spinosus ). Differs from both A. walkeri and A. spinosus in having a pair of terminal denticles on inferior appendage (versus only one). Differs from all three species in having the ventral surface of the mid-ventral spine of VI nonsclerotized, a character shared only with A. illini .

Description. Male. Length 5.4-6.0 mm (n = 3). Male genitalia: Lateral view ( Fig. 12a ), anterior margin of IX vertical on dorsal 1/8, then sloping down and forward to below midline at 45 o, then concave and sloping down and back at about 60 o to irregular ventral margin; ventral margin 1/2 length of inferior appendages; anterior and posterior margins meet on dorsal midline, forming an upturned collar. Posterior margin of IX straight, down-sloped posteriad at 40 o to base of preanal appendage, then convex to internal ridge, then nearly vertical to ventral margin. Preanal appendage rod-shaped, 1/2 length of inferior appendage, tip decurved and rounded, 12-18 setae on dorsal surface, basal 1/4 covered by IX. Dorsal margin of X sloping upward at 20-30 o from base on anterior 2/3, forming 120 o angle with distal 2/3, sclerotized on dorsal1/2 to 3/4 length, otherwise membranous except for ventral arms. Ventral arms slender, thicker and horizontal on basal 3/8, distal 5/8 straight, angling posteriodorsad at 30-40 o and continuous with darkened denticle (occasionally two denticles) at tip. Inferior appendage slightly shorter than X, length = 1.8 times depth, deepest near tip; dorsal and ventral margins divergent and straight to rounded dorsal and ventral corners. End of inferior appendage with two dark areas at mid-depth representing inward directed pair of denticles, tip of lower denticle exposed, margin concave and often irregular above and below these denticles.

Dorsal view ( Fig. 12b ). Anterior margin of IX with broad, deep, rectangular emargination; posterior margin broadly V-shaped and nearly contacting anterior margin on midline. Preanal appendages 1/2 length of X, margins nearly parallel, outer margins concave, slightly swollen near rounded tip. Dorsal, sclerotized portions of X fused on midline on basal 1/2, not conspicuous (not shown in Fig. 12b ), distal 1/2 of X membranous; outer margins of ventral arms smoothly and gently concave from base to tip of slender, darkened, terminal denticle or pair of denticles; inner margins straight, converging to swollen area near mid-length length, then diverging to rounded corner at base of terminal denticle. Large dorsal denticle at tip of inferior appendage a transverse equilateral triangle; underlying smaller denticle more slender, angling slightly posteriad, 1/2-2/3 length of dorsal denticle.

Ventral view ( Fig. 12c ). Anterior margin of IX broadly U-shaped, posterior margin forms 140 o angle between inferior appendage bases; posterior depigmented area not apparent. Inferior appendages with outer margin straight and parallel, slightly divergent to abruptly incurved tips; inner margins in contact at base, diverging at 25 o from each other to posterioventral corners. Slender, darker, ventral, more terminal denticle and larger dorsal denticle conspicuous.

Larva. We have not seen intact larvae, but sclerites from MMTs are distinctive. Sclerotized areas straw-yellow, with brown darker sutures and edges typical for genus. Frontoclypeus with pair of rounded brown muscle scars at 1/3 length, another pair a bit less conspicuous at posteriomedial “corners” of a pair of pale areas near lateral margins at mid-length; then a row of three elongate muscle scars arcing from corner to corner on distal 1/2, then a pair of elongate muscle scars at 3/4 length. Genae like those of A. walkeri , except perhaps somewhat more prominently marked, rows of muscle scars ventral to eye spot less regular and less crowded, and two additional irregular rows along ventral suture of genae. Posteriolateral 1/2 of pronotal sclerites each with about 8-10 elongate, pale muscle scars with darker brown edges.

Emergence dates. 15 April-14 July.

Distribution. AL Bibb, Jackson, Lawrence (2), Madison, Winston. KY Pulaski (13), Wayne, Warren. ME Hancock, Penobscot (2). MI Crawford. NB Sunbury. NC Nash. NS Lunenburg. ON Hastings. VA Bath (2), Montgomery, Patrick. WV Hampshire,Wayne.

Figures

Figure 10-12. Agapetus spp. male genitalia. 10) Agapetus harrisi Etnier, Parker, and Baxter. 10a, lateral view; 10b, dorsal view; 10c, ventral view of IX and inferior appendages. 11) Agapetus hesperus Etnier, Baxter, and Parker. 11a, lateral view; 11b, dorsal view; 11c, ventral view, preanal appendages not shown. 12) Agapetus hessi Leonard and Leonard. 12a, lateral view; 12b, dorsal view; 12c, ventral view of IX and inferior appendages.