Bucculatrix ambrosiaefoliella Chambers 1875

Bucculatrix ambrosiaefoliella Chambers (Figs. 118, 119, 119a.)
1875. Bucculatrix ambrosiaefoliella Chambers, Cin. Quart. Journ. Sci. II: 119.
Type, Kentucky (? Covington) [M.C.Z., Type No. 1307].
1878. Bucculatrix ambrosiaefoliella Chambers, Bull. U. S. Geol. and Geogr. Surv. of Terr. IV: 115, 116.
1882. Bucculatrix ambrosiaefoliella Chambers, " Notes on the larva of Bucculatrix ambrosiaefoliella," Canad. Ent. XIV: 153—160.
1923. Bucculatrix ambrosiaefoliella Forbes, Mem. 68, Cornell Univ. Agric. Exp. Sta.. 158.
1876. Bucculatrix rileyi Frey and Boll, Stett. Ent. Zeit. XXXVII : 219. Type
S, Dallas, Texas [B.M. ?]. (New synonymy.)
Face whitish, tuft whitish, median hairs brown, or grayish brown ; eye-caps white, antennal stalk, except at base, with alternate equal annulations of white and dark brown. Thorax ocherous, dusted with dark brown. Fore wings usually so densely overlaid with ocherous, ocherous brown-tipped and dark brown scales as completely to obscure the basic whitish ground color; costa from base to one-third brown, the brown color diverging at one-third to form a short triangular oblique streak, bordered outwardly by paler scales; at about the middle of costa an oblique dark brown streak crosses the wing blending with the dark brown area of termen and tornus ; black scales at apex and on termen below apex ; following the oblique brown streak, an oblique but slightly curved white streak, usually immaculate, and often the most conspicuous pale mark on the wing, passes to the middle of the wing, there ending in a few pure white scales, which give it the suggestion of a hook (this mark is often less clearly defined) ; costal apical area and cilia whitish, marked with several oblique lines of browntipped scales; from base just within the costal margin, a short pale ocherous or whitish streak; a streak of brown scales follows the fold for one-third the wing length, and bears on its dorsal side scattered raised scales ; on dorsum near base, a few dark brown raised scales; just beyond middle of dorsum, a dark brown and ocherous semi-oval or broad half-crescent-shaped spot, its margin toward
base bearing black raised scales, is preceded by a curved ocherous or whitisb streak which may be narrowly continued around the brown spot and enclose it; a slightly sinuous line (concave below apex) of brown and minutely blacktipped scales extends from the whitish costal cilia toward tornus. Hind wings and cilia reddish gray-brown. Anterior legs fuscous shaded, tarsal segments broadly dark-tipped ; posterior legs pale, tarsal segments narrowly dark-tipped. Abdomen pale lustrous beneath, fuscous above.
Alar expanse 7.5 to 8 mm.
Male genitalia (fig. 118). Unique and characteristic; sacculus of harpe a blunt rounded lobe indenting anellus, cucullus attenuated, its tip with short heavy modified setae, costal prong weakly articulating with transtilla, transtilla broken in middle, the ends fimbriate; socii, pendulose lobes directed ventrally, prolonged posteriorly along tegumen as narrow transversely furrowed rods ; anellus a broad tube ; aedeagus stout, long, bent and tapering, vesica with a multitude of minute cornuti ; vinculum asymmetric, left half narrow, right half produced anteriorly, twice the breadth of left half. Scale sac large, somewhat irregular in outline ; scales elongate.
Female genitalia (figs. 119, 119a). Posterior and lateral to ostium on segment 8, circular areas of which the inner half circle (i.e. toward median line) is a free, dark-pigmented flap ; toward lateral margin of tergite of 8 on each side a tuft of long scales ; short specialized scales on intersegmental membrane beneath lobes of 7 on each side of the wide ostium ; bursa copulatrix nearly filling the body from middle of segment 2 to middle of 5 ; signum a ring slightly constricting the bursa, spines of signum ribs, see Figure 119a; ductus bursae membranous from bursa copulatrix to anterior margin of 6, sclerotized in 6 and 7, and gradually widening to middle of 7, then abruptly enlarging to ostium.
Specimens examined. — 65 or 70, representing both sexes.
Kentucky: Covington (?), type, reared on Ambrosia [M.C.Z.] ; Powell County, 1 2, "probably on Solidago," imago Oct. 24, 1941 (A. F. Braun) [A.F.B.Coll.].
Ohio: Cincinnati, 1 $,2 2 , on Ambrosia arteniisiifolia L., rearing record B.1222, imagoes Sept. 9 to Sept. 19; 3 $ , on Helianthus maximiliani Schrad., rearing record B.1221, imagoes Sept. 9; 7 <$ , 8 2, August 24 to November 15 (A. F. Braun) [A.F.B.Coll.]; 1 S, Oct. 8, 3 2 , Aug. 28, Sept. 17, Sept. 29 (A. F. Braun) [A.N.S.P.] ; Brown County, 2 2, on Ambrosia arteniisiifolia, rearing record B.2213, imagoes Sept. 12, Sept. 26 (A. F. Braun) [A.F.B.Coll.].
Pennsylvania: Oak Station, Allegheny County, New Brighton, and Pittsburgh, 11, $, 2, September [U.S.N.M.] ; Oak Station, 1 $, June 12 (Fred Marloff) [Cornell U.] ; Girard, 1 2. Oct. 10 (J. R. Ever) [J.R.E.Coll.].
Missouri: Cross Keys, 2 S, "Helianthus tuberosa," "Artichoke," imagoes Aug. 23, Oct. 31 ; Blackjack, 2 2," Helianthus tuberosa," imagoes Oct. 10, Oct. 18; 1 2, "reared from Artichoke," November 7 (all Webster Groves, and determined by Satterthwait as this species) [U.S.N.M.] ; Webster Groves, 1 (sex 85
not determined), on sunflower, 8/15/30 ( Satterthwait) [U.S.N.M.] ; 2, "on sunflower," 8/10/96 (Riley Coll.) [U.S.N.M.] ; several of the Riley Collection without data [U.S.N.M.].
Iowa : Sioux City. 2 6.3 9. July and September ( C. N. Ainslie) [U.S.N.M.] ; 19," Taken from sunflower," August 4, 1916, with white cocoon (C. N. Ainslie) [U.S.N.M.],
Texas: 1 specimen, lacking head, right fore wing, and abdomen, "827, 8.X, From Boll. Texas, B. rileyella" [U.S.N.M.]; Brownsville, 1 9. "Bred from Ambrosia, Jan. 23. 09" (McMillan and Marsh Coll.) [U.S.N.M.].
California : Lonia Linda, San Bernardino County, 1 S , March 8—15 [U.S.N.M.]. (Identification verified by slide of genitalia.)
No Locality: several, "on ambrosia, 3/29/95 in warm room "; 2 (sex not determined), '' Bucculatrix on Ambrosia," slender white cocoon, 3/19/93; several without data ( Fernald Coll.) [U.S.N.M.].
The recorded food plants of B. ambrosiaefoliclla include Ambrosia artemisiifolia L., A. trifida L., and several species of Helianthus. Chambers ( 1882, loc. cit. ) describes the life history of this species in considerable detail; " the larva .... makes at first a short, tortuous, linear mine, which ends in a small blotch, with the frass in compact lines." Chambers assumes only one instar wholly in the mine, the larva moulting but once in the mine, and feeding in the mine for about a clay after this moult, then leaving the mine and feeding externally for about two days. [It is probable that earlier moults within the mine were not observed.] Following these two days of external feeding " it spins beside a rib a thin sheet of white silk, beneath which it spins a cocoonet, in which it again assumes the horse-shoe shape, and passes in about a day to second moult. Emerging from its cocoonet, it continues to feed externally for three days, when either on the plant or near to it, it spins its ribbed cocoon, in which it passes the pupa state." If Chambers' observations are correct, and only one moulting cocoon is spun after leaving the mine, it would appear that the larva spends part of the penultimate instar in the mine. Chambers describes the larva after the last moult in the mine as "striped longitudinally; there is a dorsal green stripe, margined on each side by a white line, beneath which is another green stripe on each side, containing on each segment two white spots placed obliquely, the lower spot being the largest .... the larva frequently has a faint pink tinge, and the longitudinal stripes, which are very faint at first, become darker with age." Notes under rearing record B.2213 describe the last instar larva as reddish ; a broad
mid-dorsal reddish stripe with a greenish narrower stripe each side of it, its lower edge wavy, and setal areas and spiracles greenish. These markings will distinguish the larva of B. ambrosiaefoliella from that of B. agnella when both are feeding together on the same plant.
The slender cocoon is white, with six or seven fine ridges.
The moths appear from late summer into October, and probably hibernate ; however, moths are seldom collected in spring.
The left fore wing of the specimen in the United States National Museum, labeled " B. rileyella, From Boll, Texas," which lacks head, right fore wing and abdomen, agrees exactly with Frey's description of rileyi, and with specimens reared on Ambrosia and Helianthus, and thus substantiates the synonymy.
In wing markings, Bucculatrix ambrosiaefoliella resembles B. ivella Busck ; the slightly sinuate ciliary line separates it from that species. The unusual male genitalia resemble no other species, and diverge in several respects from the usual pattern of the genus, notably in the asymmetric vinculum (a character checked by examination of several slides), the unusual socii, and the well-defined transtilla. Some characters of the female genitalia appear to ally it to the group of species with modification of the ovipositor for rasping or piercing and transfer of its function to the terminal portion of the vagina.
B. ambrosiaefoliella has been confused with pomifoliela Clemens, which appears early in the season. The fore wing of pomifoliella is somewhat broader, and in pomifoliella the outer margin of the dark streak from costa to termen is straight, and is not followed by a whitish hook-like mark.

Bucculatrix ambrosiaefoliella is a species of moth in the family Bucculatricidae. It is found in North America, where it has been recorded from California, Texas, Arizona, Pennsylvania, Kentucky, Missouri, Iowa, Maine and Ohio. The species was first described by Vactor Tousey Chambers in 1875.

The wingspan is 7.5–8 mm. Adults are on wing from late summer to October. The species probably overwinters as an adult.

The larvae feed on Ambrosia and Helianthus species and Parthenium hysterophorus. They mine the leaves of their host plant. The mine starts as a short, tortuous, linear mine ending in a small blotch. Pupation takes place in a white, slender cocoon.