Agapetus tomus Ross

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 : 41-42

Agapetus tomus Ross

Fig. 26a, 26b, 26c . Map 26

Agapetus tomus Ross 1941: 44

Type locality, Swamp Cr. 7 mi s of Dalton, Whitfield Co., GA. ( INHS)

Diagnosis. In lateral view neither the U-shaped ventral projection from the tip of the ventral arms of X nor the symmetrically concave (occasionally truncate) tip of the inferior appendage is shared by other North American Agapetus .

Description. Male. Length = 4.9-6.7 mm (n = 16). Male genitalia: Lateral view ( Fig. 26a ), anterior margin of IX with upper 1/2 convex, sloping down and forward to midline at 45 o, then concave, down and back at 65 o to convex ventral margin; ventral margin 6 times length of dorsal margin; lateral carina slopes from upper edge of preanal appendage up and forward at 10 o from horizontal; posterior margin convex and essentially vertical below preanal appendage. Preanal appendage slender at posterior edge of IX, gradually deepening to tip; extending anteriad under IX for about 1/3 its length, posterioventral corner slightly produced. Preanal appendage length = 0.6 times length of X, 1/2 length of inferior appendage, exposed portion with 10-15 erect setae near dorsal margin. Dorsal margin of X sclerotized on basal 3/ 8, distal 5/8 membranous and horizontal to sloping down and back to dorsal point of sclerotized ventral arms; ventral arms narrowest at base, a dark, lateral, external denticle apparent at 1/4 length, a Ushaped ventral projection occupies distal fifth; posterior margin vertical ± 20 o and terminates dorsad in sharp, darkened point, with adjacent small, non-pointed, darkened areas occasionally present. Inferior appendage length = 2.4 times depth; dorsal margin straight to barely sinuous to rounded posteriodorsal corner where internal denticle visible as dark area; posterior margin vertical to sloping down and back at about 20 o, slightly to definitely concave; ventral margin biconcave with obtuse ventral projection near mid-length, distal concavity more pronounced than anterior concavity; posterioventral corner rounded and with dark mark representing posterioventral denticle. Lateral surface of inferior appendage with carina extending back and slightly up from anterior articulation 5/8 distance to tip.

Dorsal view ( Fig. 26b ). Anterior margin of IX broadly and deeply concave, right and left halves occasionally separated by suture; posterior margin concave or not apparent, nearly contacting anterior margin on midline. Preanal appendage with outer margin concave, inner margin sinuate, margins subparallel, tip bluntly pointed and diverging from body axis at 45 o. Dorsal sclerotized base of X not differentiated from membranous remainder; lateral margins barely concave, parallel to body axis except pointed tips curved outward at 30 o from body axis; a dark, broad-based, pointed, lateral denticle at 1/3 length of X; inner margins of ventral arms convergent from base, in apparent contact at 2/3 length, then gradually more divergent to terminal, darkened denticle, which may be bifid or adorned with a few tiny points laterally. Inner dorsal margin of inferior appendage concave, especially at tip where curved inward (60 o) to form dorsal, terminal denticle; outer margins straight to smoothly and weakly convex; posterioventral denticle visible, much larger and more transverse than posteriodorsal denticle.

Ventral view ( Fig.26c ). Anterior margin of IX with trapezoidal emargination; posterior margin forms obtuse (120 o) angle between bases of inferior appendages; posterior 1/3 with depigmented area separated from anterior 2/3 by transverse patch of setae. Inferior appendages with outer margins nearly straight basally, becoming convex on distal 1/3 to transverse or slightly recurved, finger-like tip; inner margins straight to convex and divergent from basal contact to 2/3 length, then concave to finger-like tip; a darkened denticle present at posterioventral corner; posteriodorsal denticle often hidden.

Larva. Sclerites of head and pronotum pale, slightly darker than or as pale as other sclerotized areas. Frontoclypeus with three groups of transverse dark muscle scars, a pair just anterior to mid-length, four in a row from corner to corner, the larger two medial and more anterior, and two or three near the posterior end of the sclerite that form a triangle, point directed forward, or a line with the dark marks contiguous or nearly so. Posterior margins of frontoclypeus with darker brown border continuous with similar, slightly broader adjacent band on the genae. Genae with four large, round brown spots on each side of vertex and two rows of similar but less conspicuous brown spots behind eye, upper row with four spots, lower row with five or six spots. Pronotum with anterior 1/2 immaculate, area from and behind anterior base of foreleg with about ten brown spots per side. Mesonotum, metanotum, and tergite on IX lacking dark spots or margins, difficult to differentiate from adjacent membranous areas. Femora and tibiae freckled with brown spots. Except for dark anal claw, other sclerites straw-yellow, with brown darker markings typical for genus.

Emergence dates. 4 May-26 August.

Distribution. AL Bibb (2), Blount, Cherokee, Cleburne (3), Jefferson (2). GA Catoosa (3), Fannin, Gilmer (6), Murray, Whitfield. KY Bell (2), Breathitt (2), Green (2), Jackson, Laurel, Letcher, McCreary, Warren, Whitley. MI Livingston. MN Aitkin (2), Morrison, Pine (4). NC Cherokee. OH Portage (2). PA Somerset, Westmoreland. TN Blount (23), Bradley, Claiborne, Greene, Jefferson, Johnson (3), Morgan (3), Sevier (2). VA Smyth (6).

Discussion. We have taken A. aphallus , A. baueri , A. jocassee , A. pinatus , A. vireo , and A. walkeri with A. tomus .

Etymology. Unknown.

Figures

Figure 25-27. Agapetus spp. male genitalia. 25) Agapetus stylifer Etnier, Baxter, and Parker. 25a, lateral view; 25b, dorsal view; 25c, ventral view, preanal appendages not shown. 26) Agapetus tomus Ross. 26a, lateral view; 26b, dorsal view; 26c, ventral view of IX and inferior appendages. 27) Agapetus tricornutus Etnier, Parker, and Baxter. 27a, lateral view; 27b, dorsal view, inferior appendages not shown; 27c, ventral view of IX and inferior appendages.