202 
NORTH AMERICAN NEPTICULIDAE 
])lack; ej'c-caps silvery white, with a bluish luster, sometimes becoming black- 
ish outwardly. Thorax aud basal fourth of the fore wing shining with a 
bright blue or juirple metallic luster. Ground color of the remainder of the 
wing black. There is a rather broad shining silvery fascia just beyond the 
midille of the w ing, l)roadening and curving tow ard the base as it ap])roaches 
the dorsum, ^^d^en viewed at some angles, this fascia shows pale blue re- 
flections. Cilia shining pale bluish, with a line of dark scales through their 
middle. Hind w ings and cilia gray, with a bluish luster in the female; in the 
male with the costal margin beset with black scales, and a bunch of black 
hair-scales near the middle of the dorsal margin ; an oval pale yellowish patch 
of androconia. Legs metallic iridescent. Abdomen dark brow n above with a 
faint bluish luster, much paler beneath and bluish. 
Expanse . — 4 mm. 
Locality. — Ohio. 
The larvae form long serpentine mines (Fig. 51), 13 or 14 cm. 
in length, in leaves of sugar maple (Acer saccharum) and occasion- 
ally red maple {Acer rnbrum), in which the loosened epidermis is 
pale green and a black line of frass extends through the middle 
of the mine. The numerals in the figure mark the length of the 
mine on the respective dates indicated. Larva pale green; 
cocoon ocherous, regularly oval, much flattened and smooth, 
with projecting rim extending entirely around it. 
INIined leaves may be collected in early July and late August; 
sometimes the larvae of a third generation are found in October. 
Moths from the overwintering pupae emerge in May and June. 
Food Plants, Mines and Larvae 
The characteristic and constant form of the mine, and the fact 
that each species of Nepticida and its allies is confined to one 
plant or at most to a few closely related plants, permits of ready 
identification in the early stages. Because of this fact, the list of 
food plants and descriptions of mines occurring on them has been 
compiled in the hope that it will be an aid to the collector in 
identifying his specimens. 
Salix spp., \^'illow': 
(1) N. pallida; mine linear, narrow' at the end (Fig. 50). 
(2) N. fuscotibiella; mine linear, gradually broadening, club shaped at 
the end, sometimes blotch-like toward the end (Figs. 25, 44). 
Popidns (jrandidentata, Poplar: 
A) E. popidella; globular sw'elling of petiole close to leaf. 
Popidns deltoides, Cottonwood: 
(l)'Ab populetoruni; whitish mine gradually increasing to a breadth of 
2 to 2.5 mm. at end (Fig. 8). 
