Agapetus gelbae 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 : 16-17

Agapetus gelbae Ross

Fig. 9a, 9b, 9c . Map 9

Agapetus gelbae Ross 1947: 47

Type locality, May’s Spring 2 mi sw of Bloomington, Monroe Co., IN. ( NMNH)

Diagnosis. Inferior appendages in lateral view with distal 1/3 produced ( Fig. 9a ) into a long, finger-like projection, its depth about 0.4 times basal depth (versus inferior appendages rhomboid, rectangular, ovoid, gradually tapering, distally emarginated, or produced mesally or ventrally in other species of eastern and central North America).

Description. Male. Length 5.0- 5.1 mm (n = 3). Male genitalia: Lateral view ( Fig. 9a ), anterior margin of IX slopes down and forward at 60 o to below midline, then down and nearly vertical to convex ventral margin; dorsal margin short, horizontal, 1/8 length of ventral margin; posterior margin straight, sloped down and back at 70 o to mid-depth, then down and forward at 10 o to ventral margin; both anterior and posterior margins thickened. Preanal appendage extending posteriad to middle of X; convex dorsal margin and concave ventral margin parallel, posterioventral corner somewhat produced, length = 2.5 times depth, about 10 long, erect setae along exposed dorsal margin. Segment X sclerotized throughout, more heavily so on ventral arms and posterior margin; ventral margin with basal 1/4 convex, distal 3/4 concave, terminating in a short, dark denticle continuous with ventral margin; heavily sclerotized area expanding to form triangle on distal 1/3 that extends to darkened denticle at posteriodorsal corner; both denticles on X short and blunt; posterior margin nearly perpendicular to ventral margin, concave or with shallow, angular emargination just above mid-depth; dorsal margin sloped irregularly upward from base to midlength, then downward to base of posteriodorsal denticle, with a slight concavity at 1/4 length. Inferior appendage extends slightly past end of X, length 4 times maximum depth; distal 1/3 finger-like, less than 1/2 as deep as basal 2/3; dorsal margin concave on basal 1/3, then straight or slightly convex to rounded tip where a subterminal, submarginal denticle is visible as a dark spot at the termination of a darkened line nearly parallel to the dorsal margin; ventral margin convex on basal 2/3, separated by a concavity from distal 1/3; scattered, darkened marginal denticles often present from slightly past middle of appendage to near its base, distal denticles largest.

Dorsal view ( Fig. 9b ). Anterior margin of IX broadly V-shaped, meeting at midline at 110 o; posterior margin produced on middle 1/4, tip truncate, poorly differentiated from X, length at midline = 1/4 length of preanal appendages. Preanal appendages with inner and outer edges straight and parallel basally, inner margin rounded near tip, outer margin slightly out-curved near tip. Segment X with ventral arms convergent, meeting at mid-length at 40 o angle, then divergent at same angle to terminal dorsal denticle; denticle at posterioventral corner of X barely visible as darkened, triangular area medial to dorsal denticle. Outer sides of X sclerotized, dorsal surface also sclerotized including a triangular area with base continuous with truncate posterior extension of segment IX; this area may actually be membranous.

Ventral view ( Fig. 9c ). Anterior margin of IX slightly concave; posterior margin forms 145 o angle with bases of inferior appendages, which are slightly separated; a subcircular to subtriangular (apex directed anteriad) depigmented area present, extending from inferior appendage bases forward 2/3 distance to anterior margin of IX; no fringe of setae associated with anterior margin of depigmented area. Inferior appendages with outer margin smoothly convex to rounded tip, with weak denticle forming posteriomedial corner; inner ventral margin concave and with denticulate ridge from slightly past middle of appendage to near its base. Inner dorsal margin of inferior appendage concave, distal 1/3 a narrow denticulate ridge with denticles tiny and irregular, terminating at posteriomedial corner of appendage. Ventral arms of X (not shown in Fig. 9c ) with both terminal denticles visible.

Larva. Head and sclerites on IX and X brown, notal sclerites and sterna slightly paler, legs yellow. Frontoclypeus with a pair of elongate pale marks on anterior margin narrowly separated at midline; a pair of round, marginal pale spots at mid-length; a transverse arc of 3 pale muscle scars across middle of posterior 1/2. Genae with inconspicuous pale muscle scars below and behind circular, pale eye area; posterior third paler than anterior 2/3 on MMT sclerites. Pronotum with semicircular dark spot at margin where foreleg attaches; a few pale muscle scars in middle portion of sclerite. Other dark markings associated with sclerites typical for genus.

Emergence dates. 22 April-7 June.

Distribution. AL Florence, Lauderdale. IN Monroe (3). TN Hardin, Lawrence, Lewis, Sumner.

Discussion. We have taken A. gelbae with A. aphallus and A. avitus . Similarities of heavily sclerotized areas on X suggest an affinity with A. crasmus and A. diacanthus , while shape and denticulation of the inferior appendages suggest A. pegram / A. stylifer affinities.

Etymology. Named in honor of Miss Ruth Gelb, who first collected the species.

Figures

Figure 7-9. Agapetus spp. male genitalia. 7) Agapetus diacanthus Edwards. 7a, lateral view; 7b, dorsal view; 7c, ventral view of IX and inferior appendages. 8) Agapetus flinti Parker, Etnier, and Baxter. 8a, lateral view; 8b, dorsal view; 8c, ventral view, segment X not shown. 9) Agapetus gelbae Ross. 9a, lateral view; 9b, dorsal view; 9c,