Cosmiotes illectella Clemens 1860

Cosmiotes illectella Clemens (Figs. 16, 16a, 16b, 50, 103, 103a.)
1860. Cosmiotes illectella Clemens, Proc. Acad. Nat. Sci. Phila., p. 9. Type
locality, Pennsylvania (?Easton). 1872. Eleichista {Cosmiotes) illectella Stainton, Tineina of No. Amer., p. 98. 1903. Elachista illicitclla Dyar, Bull. 52, U. S. N. M., p. 536 (misspelling).
1923. Aphelosetia illectella Forbes, Mem. 68, Cornell Univ. Agric. Exp. Sta., p. 223.
1860. Elachista praematurclla Clemens, Proc. Acad. Nat. Sci. Phila., p. 172.
Type S, Pennsylvania [A. N. S. P., Type No. 7398]. (New synonymy.) 1872. Elachista praematurclla Stainton, Tineina of No. Amer., p. 133. 1874. Elachista praematurclla Chambers, Canad. Ent., vi, pp. 76-77. 1903. Elachista praematurclla Busck, Proc. Ent. Soc. Wash., v, 203. 1914. Elachista praematurclla Braun, Ent. News, xxv, 114.
1922. Elachista praematurclla Braun, Canad. Ent., liv, 94.
1923. Aphelosetia praematurclla Forbes, Mem. 68, Cornell Univ. Agric. Exp. Sta., p. 223.
1876. Elachista cristatella Chambers, Canad. Ent., viii, 172. Type S, Kentucky [MC. Z.]. (New synonymy.)
1880. Elachista albapalpella Chambers, Journ. Cin. Soc. Nat. Hist., in, p. 294. Type 9, Amherst, Massachusetts [U. S. N. M., Type No. 1035]. (New synonymy.)
Head fuscous, irrorated with dark gray, face sometimes paler, more or less silvery, but scales usually tipped with dark gray ; palpi fuscous, paler and sometimes whitish above, a black spot at base of third segment above ; antennae dark fuscous with narrow paler annulations. Fore wing, male : fuscous, densely dusted, the paler bases of the scales grayish white; just before middle a slightly oblique irregular narrow fascia (in the form described as cristatella, much reduced and indicated only by a broken line) ; posterior to the fascia below the fold an elongate patch of black slightly raised scales, not contrasting in the darkest specimens ; at two-thirds, a white costal and an opposite dorsal spot, occasionally obsolete, a few black scales sometimes separating their apices; usually a few white scales at extreme apex ; cilia fuscous, whitish around apex, the marginal scales projecting into them conspicuously black-tipped. Fore wing, female : darker than in the male, more evenly dark brown or black, but when irrorated, paler before the fascia, especially in the late fall and early spring generations ; fascia broad, silvery white, dorsal and costal spots silvery white, never reduced in size ; cilia fuscous, white around apex, the black-tipped marginal scales white at base around apex, and forming a more or less conspicuous white transverse mark in the cilia. Flind wings and cilia fuscous, darker in the female. Legs gray, hind tibiae with a white band before middle and at apex. Abdomen fuscous, genital segments of male clothed with long yellowish white hairs.
Alar expanse : 6 to 7.5 mm., rarely 8 mm.
Male genitalia: as in scopulicola (figs. 56, 56a), except that the setae of the anellus lobes are somewhat shorter and finer.
Female genitalia (figs. 103, 103a) : ostium and sclerotized portion of ductus bursae densely spinulate, ductus bursae as wide as the ostium through most of segment 7, then abruptly narrowing at the anterior margin of segment 7; signum a pair of opposite large spines, accessory spines absent or minute.
More than a hundred specimens of both sexes have been examined. C. illectella is represented in collections from Ontario, Massachusetts, New York, New Jersey, Pennsylvania, Tennessee, Kentucky, Ohio and Michigan (in both the Lower and Upper Peninsula) and probably occurs throughout the eastern United States and Canada.
The mines are found on leaves of many species of grass, among them Poa pratensis (Kentucky Blue Grass), Poa spp., Agrostis spp., Hystrix sp., Elymus sp., Oryzopsis sp., Bromus sp., and Phleufn (timothy). .Mining larvae may be found almost throughout the year, even in the winter, and produce imagoes within a few weeks. The mine starts as a fine line, gradually increases in breadth and on the narrow-leaved grasses, occupies the width of the blade. It is usually whitish, with parenchyma all consumed, and is about equally visible from either leaf surface.
The larva varies in color to some extent with the food plant, but is usually greenish yellow, with the prothoracic shield marked posteriorly with a transverse brownish bar on either side of the mid-line, and fainter longitudinal markings down each side of the mid-line. Pupation takes place beneath a dense white meshwork of irregularly placed silk strands. The pupa (fig. 50) is characteristic of the genus, with the two backwardly pointing spines of the vertex; specifically it is distinguished from that of scopulicola by the two small tubercles of the prothorax.
The marked sexual dimorphism is responsible in part for the synonyms. The description of illectella applies to the female; in the type, apparently, veins R 4 , R-, and M t separated from their stalk close together, a condition occurring rarely in the female (fig. 16b) ; the more usual condition is that shown in figure 16. In the male (fig. 16a), the point of separation of R 4 is usually farther basad than in the female. The type of praematurella is a male with the fascia and costal and dorsal spots distinct, and a few white scales projecting from the extreme apex of the wing. Albapalpella by genitalia of the female type is a synonym ; cristatella is a pale irrorated male, with obsolescent white marks and conspicuous patch of black raised scales near dorsal margin beyond the fascia.