Bucculatrix ainsliella Murtfeldt 1905

Bucculatrix ainsliella Murtfeldt (Figs. 19, 19a, 221. 222, 222a, 222b.) 1905. Bucculatrix ainsliella Murtfeldt, Canad. Ent. XXXVII: 218. Type $, with genitalia slide by Busck, Olmstead County. Minnesota [U.S.N.M., Type No. 65035]; allotype 9, with genitalia slide by Busck, Olmstead County, Minnesota [U.S.N.M.] ; both pinned on the same mount, and here designated type and allotype. 1923. Bucculatrix ainsliella Forbes, Mem. 68. Cornell Univ. Agric. Exp. Sta., p. 159.
Face creamy white, tuft white laterally, dark brown centrally; eye-caps whitish, dotted with brown and dark brown on posterior margins, antennal stalk whitish with dark brown annulations and with intervening white segments producing a characteristic marking as follows: basal half of stalk regularly annulate, then follow one white, two dark brown, one white, four dark brown, one white segment, followed by regularly annulate segments, last few segments pale. Thorax whitish, densely dusted with dark brown-tipped scales which form several denned dark marks. Whitish ground color of the fore wing more or less obscured by the dense dusting of dark brown-tipped scales, of which the more broadly dark-tipped scales form the dark markings. The species varies greatly in density of dusting and definition of markings, and thus the markings described may not always be discernible. A dark shade along costa broadens outwardly to beyond middle of costa, narrowing below costa and as an oblique streak passing across the wing to termen there meeting a small patch of black scales ; in the middle of the wing, a short streak of whitish scales lies along the outer border of this dark oblique streak; the dark shade along costa may be indistinctly interrupted near base and before middle by slightly paler oblique shades ; on the middle of the dorsal margin a half-oval conspicuous brown spot, straight on the dorsal margin, and bearing within its inner edge a patch of black raised scales, and bordered before and behind and narrowly above by whitish scales ; apical area of wing less densely dusted, but with an aggregation of dark scales at extreme apex ; cilia with a median line of dark-tipped scales. Hind wings pale silvery gray, cilia tinged with fuscous. Legs and underside of body shining gray.
Alar expanse 7 to 8 mm.
Male genitalia (figs. 222, 222a, 222b). Harpe setose, with curved process at apex, the concave base appressed to the bulbous base of aedeagus ; a narrow sinuate band may represent transtilla; socii elongate, setose, with a row of a few stronger setae inwardly ; anellus absent ; aedeagus narrow cylindric, enlarging to a strongly sclerotized bulbous base, with conspicuous cornuti, consisting of two parallel rows of strong curved setae ; anterior to the bulbous base, a more
membranous narrow segment curving to the left and posteriorly ; vinculum and tegumen weakly sclerotized. Scale sac and the scales very elongate.
Female genitalia (fig. 221). On anterior dorsal margin of segment 8, a mass of small dark scales, inserted on a broad triangular area (only a few of the scales shown on the figure) ; ostium oval, ductus bursae wide and strongly sclerotized near ostium, abruptly narrowing anterior to the sclerotized section, with inception of ductus seminalis just anterior to the sclerotized section; ductus bursae very long, several times the length of the body, coiled, and, except in its posterior third, armed with rows of teeth ; signum a ring, made up of separated groups of spined ribs.
Nearly 100 specimens representing both sexes have been examined, including type material in the United States National Museum. Some twenty-five specimens from Rochester, New York, in the National Museum (Kearfott Collection) are erroneously labeled " Topotype." In the various collections, specimens have been examined from North Carolina (Highlands, 3865 feet) and South Carolina (Cherry Hill Recreation Area, 2000 feet, Oconee County), collected by R. W. Hodges as part of a project sponsored by the American Philosophical Society; from New Jersey (Essex County Park and Watchung Mts. ), Pennsylvania (Pittsburgh, one specimen only), New York (Rochester, Long Island, Monroe County), Connecticut (East River, New Haven), Massachusetts (Barnstable, Beverley, Martha's Vineyard), Maine (Augusta, Bar Harbor), Nova Scotia (Annapolis, "bred from red oak "), Ontario (St. Catherines, " host, Quercus borealis "), Michigan (Wayne County), Minnesota (Olmstead, the type material). Some of these specimens are accompanied by cocoons, some bear notations " cocoon on oak ", "on oak," on " Quercus rubra/' " on chestnut," " bred, skeletonizer Quercus borealis."
This widely distributed common species was originally described from Minnesota specimens. Its distribution appears to follow a definite pattern. It is reported to be present in great numbers on the oaks along the Blue Ridge Parkway and has been collected in North Carolina and in adjacent South Carolina. From there is occurs northward along the Appalachian Highlands and the coastal area of New England to Nova Scotia and west across the North to Minnesota. There are no records from the more southern midwestern states.
Bucculatrix ainsliella is sometimes common enough to be of economic importance. From Miss Murtfeldt's account I quote the following: "Some of the leaves received from my correspondent [C. N. Ainslie] had attached — generally to the under surfaces — crowded groups of from twenty to thirty cocoons, and on many of the grass blades were double rows from one and one-half to two inches in length."
Various species of oak and also chestnut are attacked by the larvae. Black oak (Oncrcus veluiina Lam.) appears to be the preferred food in the type locality (Minnesota), red oak (Quercus rubra L.) in other localities. The short thread-like mine (observed on red oak near St. Cloud, Minnesota) follows the midrib or a principal vein for most of its length, then sharply diverges from the vein ; the exposed larva feeds on the underside of the leaf, skeletonizing it. The white cocoon, tapering to each end, has six rather low and sometimes indistinct ridges. The winter is passed in the pupal state, with emergence the followingspring. The specimens examined bear dates from April to early August and to early September in North Carolina. These later dates suggest either a long period of emergence, or in favorable localities, a possible summer generation with feeding larvae in late June or early July.
The Nova Scotia series is paler and less densely dusted, with the dark marks more sharply contrasting. The peculiar antennal markings are present also in B. pomifoliella, the wing markings of which are similar. Genitalia of both sexes serve to separate B. ainsliella from all other species of our fauna. Although the genitalia display much modification from the general type of the section, the harpe of the male indicates its assignment to this section.
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Bucculatrix ainsliella, the oak leaf skeletonizer or oak skeletonizer, is a moth species of the family Bucculatricidae. It is found in the northern part of the United States, down to North Carolina and Mississippi and the Southern parts of Canada, including British Columbia. In 2011 it was discovered in the Netherlands and Belgium. It was first described in 1905 by Mary Murtfeldt.

The wingspan is 7–8 mm. Adults are on wing between February and August depending on the location.

The larvae feed on Quercus species, first as leaf miner and later feeding externally.