Elachista orestella Braun 1908

Elachista orestella Busck (Figs. 62, 62a, 111, Ilia.)
1908. Elacliista orestella Busck, Canad. Ent., xl, 196. Type $ (without abdomen), Oak Station, Allegheny County, Pennsylvania, [U. S. N. M., Type No. 11563].
1923. Aphclosctia orestella Forbes, Mem. 68, Cornell Univ. Agric. Exp. Sta., p. 220 ( in part ) .
Head and palpi typically pure white (second segment of palpus in male sometimes shaded outwardly with fuscous) ; antennae white near base, shading to fuscous at tips. Thorax and fore wings usually pure white, faintly shining, rarely with a faint yellowish tinge especially along costa ; at two-thirds the length of the fold an elongate black spot, and obliquely above it at the end of the cell, a similar, but usually smaller black spot; on the dorsal margin, just basad of the end of the fold, a cluster of blackish or fuscous-tipped scales is almost always present ; there may be a few fuscous-tipped scales scattered over the wing surface, usually confined to the apical third of the wing, but in one male, the number of these dark-tipped scales is greatly increased, and they occur over the entire wing surface and form ill-defined patches around the black spot at end of cell, at apex and along termen near tornus. Cilia white, in the darkest specimen pale fuscous toward tips; the marginal row of scales around apex and along termen usually black tipped, the tips forming a fine dark line in the cilia from costa before apex nearly to tornus. Underside of fore wings usually white, sometimes faintly ocherous. Hind wings and cilia white in both sexes ; rarely with a faint ocherous tinge. Legs white, more or less shaded with fuscous, fore pair fuscous inwardly. Abdomen white, with slight fuscous shading.
Alar expanse: 9.5 to 11 mm.
Male genitalia (figs. 62, 62a) : uncus lobes with a few short marginal setae; gnathos elongate oval ; harpe broad, costal margin thickened, sacculus processes stout, dorsally obtusely angulated ; lateral margins of anellus strongly sclerotized and produced beyond the posterior margin of each lobe, which bears a group of a few short setae; vinculum broadly rounded; aedeagus tapering, cornutus a curved spine.
Female genitalia (figs. Ill, Ilia) : bursa copulatrix pear-shaped, signum consisting of three connected teeth and one or two smaller teeth on an elongate spined patch ; in addition, two elongate finely spinulate patches, one dorsal and one ventral ; outer surface of ductus bursae from the bursa into segment 7 with a broad longitudinal dentate band ; a short membranous portion follows, then a sclerotized band before the opening into a spinulate depression of the genital plate.
Specimens examined: 115,7$.
Pennsylvania: Oak Station, Allegheny County, 2 type, June 11, 1907 (Fred Marloff), [U. S. N.M.];3 3, May 21, 1911 ( F. Marloff), [U. S. N. M.], 1 S, same date, [M. C. Z.] ; Hazleton, 1 2, 5-18-97 (W. G. Dietz), [M. C. Z.].
New York: Ithaca, 1 S, 11 Aug., 1924 [J. R. Eyer Coll.]; Perry. 1 <J , 14 Aug., 1918 [J. R. Eyer Coll.] ; "Cent. N. Y.." 2 2 , 6-1-99 and 6-9-99 [M. C. Z.] ; Ramapo, 1 $ May 27, 1900 (W. D. Kearfott), [U. S. N. M.].
New Jersey: Essex Co. Pk., 2 S, July 22 and Sept. 7, 06, Trap (W. D. Kearfott), [U. S. N. M.].
Massachusetts: Cohasset, 2 S, July 2, 07 (Owen Bryant), [U. S. N. M.].
Quebec: "Westmt," 1 2 (A. F. Winn), [U. S. N. M.].
Illinois: Chicago, 2 2 [M. C. Z.].
Food plant and early stages unknown.
Elachista orestella may be separated on adult markings from E. epimicta by the more basad position of the plical spot, by the cluster of dark scales on the dorsal margin near the end of the fold, and by the white hind wings of both sexes. The single darker male (referred to in the description) from Essex County Park, N. J., July 22, agrees exactly in genitalic characters with typical white males. Genitalic characters of both sexes suggest relationship to acenteia Braun.
In Forbes, Lepidoptera of New York, page 220, the description of the adult moth applies to orestella, the remarks on food plant and early stages apply to epimicta.

Likely not a concern because this genus is widespread.

Moths have been observed flying as early as April through to September (Kaila 1997).

In Canada E. orestella can be found in Alberta, Labrador, New Brunswick, Newfoundland Quebec and Yukon (Kaila 1997). In the United States, specimens have been collected in Alaska, Illinois, Massachuesetts, Minnesota, Nebraska, New Jersey, New York and Pennsylvania (Kaila 1997).

Elachista orestella is categorized within the nearctic E. argentella group (Kaila 1997). This group is characterized by having a smooth scaled head, slightly raised neck tufts and antennae that are approximately 2/3 the length of the forewing (Kaila 1997). The wings are lanceolate; the hindwings are grey and translucent and the forewings acute at the tip and typically white (Kaila 1997). Elachista orestella may be mistaken for E. aurocristata but can be separated by the overall size, colouration and genitalic features (Kaila 1997). With a forewing length between 3.1 to 5.7 mm, E. orestella is smaller (Kaila 1997). In E. orestella dark scales create two spots at the midpoint of the forewing and at the 2/3 of the wing at the fold (Kaila 1997). These scales are present but fainter and brownish in E. aurocristata (Kaila 1997). The aedeagus of male E. orestella is shorter than the length of the tegument and uncus combined (Kaila 1997).

Nearctic E. argentella members live in a variety of habitats including arctic tundra, alpine meadows, wetlands and grassland prairie (Kaila 1997). In Alberta, E. orestella adults have been encountered in montane habitats.

Elachista adults are typically active during dusk and dawn periods can sometimes be nocturnal. The adults of this genus are not readily attracted to lights (Kaila 1997).

Though largely unknown, larval habits of the E. argentella group are reportedly Poaceae leafminers (Kaila 1997)

Elachista orestella is a moth of the family Elachistidae. It is found in North America in Alberta, Labrador, New Brunswick, Newfoundland and Labrador, Quebec, Yukon, Alaska, Illinois, Massachusetts, Minnesota, Nebraska, New Jersey, New York and Pennsylvania.

The length of the forewings is 3.1–5.7 mm. The forewings are broad. The costa in the basal sixth is grey, while the ground colour is white, irregularly dusted with grey tips of scales especially in distal part. The hindwings are shining light grey and translucent. The underside of the wings is grey.