Elachista epimicta Braun 1948

Elachista epimicta new species (Figs. 6, 15, 39, 61, 61a, 107.)
1920. Elachista orestella Braun (not Busck), Ohio Journ. Sci., xx, 171, 172.
1921. Elachista orestella Braun (not Busck), Ohio Journ. Sci., xxi, 209. 1923. Aphclosetia orestella Forbes (not Busck) in part, Mem. 68, Cornell Univ.
Agric. Exp. Sta., p. 220. 1933. Elachista orestella Braun (not Busck), Trans. Am. Ent. Soc, lix, pp. 238, 241, ct al.
Head white, palpi white, the second segment outwardly shaded with dark fuscous, more deeply so in the male; antennae whitish, with indistinct slightly darker annulations, most noticeable in the female. Fore wings white, sometimes a faint ocherous shade along costa ; on the fold at 4/5 its length a brownish or blackish spot, variable in size and somewhat irregular; at end of cell a similar spot, often smaller than the plical spot, and sometimes absent ; except for these two spots, the wings may be immaculate pure white, or there may be widely scattered pale fuscous scales, which rarely (in males) tend to be arranged in lines. Cilia white, the row of scales around apex minutely black-tipped, the black tips forming a fine even line through the cilia; this line is at least partially indicated even in the whitest specimens. Hind wings in the female varying from almost pure white to faintly grayish ocherous tinged; much darker in the male, pale ocherous fuscous. Legs yellowish white, the fore legs inwardly shaded with dark fuscous. Abdomen white, shaded more or less with pale ocherous fuscous.
Alar expanse: 10 to 13 mm.
Male genitalia (figs. 61. 61a) : uncus lobes with a few short marginal setae; gnathos ellipsoidal ; ane'lus very deeply cleft, the lobes slender and elongate, obtusely angled dorso-laterally at the point of articulation with the outgrowth from harpe. setose toward tip ; sacculus processes long, slender ; vinculum produced, the produced sides parallel ; aedeagus large, broad at base, tapering to the narrow apex ; cornutus a very long acutely pointed spine.
Female genitalia (fig. 107) : bursa copulatrix in the second abdominal segment, spiculate, signum a large nearly circular dentate patch; ductus bursae very long (longer than the body), narrowing and several times coiled, then gradually widening to near ostium where, after the inception of the ductus seminalis, it abruptly narrows and is strongly sclerotized to the small circular ostium.
Type. — 6, Cincinnati, Ohio, under rearing" record B.975, imago .May 12, 1918, [A. F. B. Coll.].
Allotype. — 2 , Cincinnati, Ohio, under rearing record B.975, imago May 16, 1 9 18, [A. F. B. Coll.].
Paratypes. — 10 6 , 8 2 , Cincinnati, Ohio, under rearing record B.975, w ' tn dates of emergence from May 10 to 16, 1918, [A. F. B. Coll. and A. N. S. P.] ; I i , Cincinnati, Ohio, rearing record B.1032, imago May 5, 1920, 1 2 , rearing record B.1033, imago May 5, 1920; 4 6 , 2 2 , Cincinnati, Ohio, taken on the wing, May 16 to June 1, [A. F. B. Coll. andU. S. N. M.].
The preferred food plant is Hystrix patula Moench. ; mines also occur on Elymus spp. The larva mines the basal overwintering leaves from October or November until May of the following spring. The mine at first lies near the upper epidermis (which by a twist in the leaf faces downward in Hystrix) ; part way along the length of this early mine, the epidermis is wrinkled, drawing the leaf into a fold several centimeters long where the leaf tissue is not consumed. Later the mine broadens and may be several inches long; here the leaf tissue is consumed and the epidermis of the mine grayish. Occasionally the larva makes a second mine, entering at the tip of the leaf, and consuming all the leaf tissue within the mine. The larva is pale greenish yellow or
grayish ; the prothoracic shield with two rather broad dorsal stripes, posteriorly darkening and each ending in a black spot.
Pupa (fig. 39) in a slight cocoon, cuticle shining.
The figure (pi. II, fig. 15) illustrates the typical venation of this section, with veins R 4 and R.-, of the fore wing stalked, and cell of the hind wing closed, with the medial stem partially preserved.
This is our broadest-winged white species.
Small females marked only with the plical and discal dots, and with white hind wings are almost indistinguishable from E. orestella Busck. In E. orestella, however, a few dark scales projecting into the cilia at tornus are almost always present, and the plical spot is situated at 2 /j, the length of the fold. On genitalic characters the two species are abundantly distinct. The usual wing expanse of epimicta is greater than that of orestella.
Through an unfortunate misidentification of this species as orestella Busck, a number of references to it as orestella have crept into the literature ; all of my previous remarks on eastern specimens under the name orestella refer to E. epimicta. The remarks on the early stages of E. orestella in Forbes, Lepidoptera of New York, apply to this species, not to E. orestella.

Elachista epimicta is a moth of the family Elachistidae. It is found in Alberta, Alberta, British Columbia, Manitoba, Saskatchewan, Colorado, Illinois, Ohio and South Dakota.

The length of the forewings is 4.6–7.1 millimetres (0.18–0.28 in). The costa in the basal 1/6 of the forewings is grey. The ground colour is white, with a variable amount of dirty yellowish tinge and often dusted with light grey tips of scales. There is often an indistinct dark brownish-grey spot in the middle of the wing at the fold and another similar spot at 2/3 of the wing. The hindwings are grey and the underside of the wings is grey.

The larvae feed on Hystrix patula and Elymus species. They mine the leaves of their host plant. The mine has the form of a blotch mine and occupies the apical one third of the leaf. The species overwinters in the larval form.