Bucculatrix canadensisella

Bucculatrix canadensisella Chambers (Figs. 34, 176, 198, 199, 199a.)
1875. Bucculatrix canadensisella Chambers, Canad. Ent. VII : 146. Type ? , "N. S." (? Nova Scotia) [U.S.N.M., Type No. 5775]. [A "type" also in M.C.Z.]
1923. Bucculatrix canadensisella Forbes, Mem. 68, Cornell Univ. Agric. Exp. Sta., p. 158.
1927. The Biology of the Birch Leaf Skeletonizer, Bucculatrix canadensis ella, Chambers. Friend, Roger B., Conn. Agric. Exp. Sta. Bull. 288. (A detailed treatment, with map of distribution and extensive bibliography.)
Face whitish, more or less brownish tinged, tuft white, centrally brown ; eyecaps white, antennal stalk with narrow brown annulations. Thorax brown, tegulae white, the white sometimes spreading to cover all but a narrow middorsal stripe. Base of wing white, the white color sometimes spreading outwardly below fold, and rarely confluent with the white dorsal spot ; ground color of the fore wing dark brown, reddish brown, or sometimes paler fuscous and then more or less irrorated ; from basal fifth of costa an oblique streak, broadest on costa, sometimes meeting the white oblique dorsal spot placed before middle of dorsum, but more often separated from it by ground color ; a patch of black raised scales borders the dorsal spot posteriorly; just before middle of costa and at three-fourths, oblique white streaks, the second the longer ; a little anterior to the second of these, a less oblique dorsal streak; near apex a white mark, widest on costa, curves to termen, enclosing the black apical spot ; a line of black-tipped scales curves around the black apical spot from the white costal mark to tornus, the scales less broadly black-tipped toward tornus ; cilia reddish tinged. Hind wings gray, the cilia brownish or reddish tinged. Legs brown outwardly, tarsal segments broadly brown-tipped. Abdomen silvery white beneath.
Alar expanse 7 to 8.5 mm.
Male genitalia (fig. 198). Harpes typical of the section, setose outwardly, terminating at apex in a small pointed process, a small basal process ; socii short, broad, setose, sinus between them shallow ; aedeagus stout, tapering to the acutely pointed tip ; vinculum a very narrow sclerotized band. Scales of scale sac of two kinds, slender and pointed and broadly oval.
Female genitalia (figs. 199, 199a). Both dorsal and ventral posterior margins of segment 7 fringed with long specialized scales ; on the intersegmental membrane and ventral to ostium, a dense tuft of specialized scales on each side of mid-ventral line ; on sternite of segment 8, on each side of ostium, a large dense patch composed of several rows of specialized scales ; on anterior margin of tergite of 8, a row of very small scales, emarginate mid-dorsally ; margin of ostium sclerotized, with two outwardly directed acute processes ; signum ribs with long spines posteriorly, grading anteriorly to short acute spines.
Some 150 specimens, including the types, and representing both sexes, have been examined in the collections of the United States National Museum, Academy of Natural Sciences of Philadelphia, Canadian National Collection, in my own collection, and in other collections.
Friend {I.e. ) has mapped the distribution of this very common species, basing his map on records available to him at that time ( 1927 ). As shown on his map and referred to in the text, B. canadcnsisclla occurs in the Canadian provinces from New Brunswick to British Columbia; to these records I add Nova Scotia and Prince Edward Island ANNETTE F. BRAl'N 149
[C.N. Coll.]. His records include stations in the New England States, New York, Michigan, Wisconsin and Minnesota; it is also recorded [A.N.S.P.] from Hazleton, Pennsylvania " bred from Betula nigra " and from New Jersey, Whitesbog. The southern record from North Carolina is based on two females reared from Betula lutea Michx. f.. Eagle's Nest, altitude 5000 feet [A.F.B.Coll.]. In addition, mines have been observed, but no moths reared, on Betula lutea on the Appalachian Trail, near Newfound Gap, Great Smoky Mountains, Tennessee at an altitude of approximately 5000 feet, and on the summit of Big Black Mountain, Kentucky, altitude 4000 feet; that is, it may apparently be found along the higher summits of the Southern Appalachians. To these, I add a disjunct occurrence of the species from Colorado : Moraine Park, Rocky Mountain National Park, 2 <? , reared on Betula occidentalis Hook. [A.F.B.Coll.].
The mine is a very narrow and contorted linear mine, 15 to 20 mm. in length ; in the last two instars the larvae feed externally, skeletonizing the leaves, but leaving the upper epidermis intact. Feeding normally takes place on the underside of the leaf; however, in the North Carolina and in the Colorado specimens, larvae fed on the upper surface of the leaf. Recorded food plants in the East include Betula populifolia Marsh., B. papyrifera Marsh, (across Canada), B. lutea Michx. f., B. leuta L., B. nigra L. and the European B. alba L. ; in Colorado, B. occidentalis Hook. The brown cocoon is rather short and rounded at both ends, with five or six prominent ridges. There is apparently but one generation a year. The depredations of the larvae have been the subject of a number of economic papers.
Bucculatrix canadcnsisella is allied to B. coronatella, agreeing with it in configuration of markings, but at once separated from that species by the dark brown or fuscous color of the fore wings.