162 
NORTH AMERICAN NEPTICULIDAE 
CC. Media of fore wing single-branched (veins four and five absent). 
, D. Middle spurs of posterior tibiae in or above the middle . 1. Nepticula 
DD. ISIiddle spurs of posterior tibiae below the middle. 
2. Ectoedemia 
AA. Rs (vein seven) of fore wing absent [Trifurcula] 
1. NEPTICULA von Heyden^ 
Nepticula von Heyden, Berich. Vers. Naturf. Mainz, 201, (1842); Zeller, Linn. 
Ent., iii, 249, 301 to 303 (1848). Type: Tinea aurella F. 
Generic characters .- — Basal segment of antennae dilated and 
concave beneath to form a large eye-cap. Vliddle spurs of pos- 
terior tibiae in or above the middle. Fore wings elongate ovate, 
pointed; hind wings | to f. 
Venation. (Figs. 1, 2 and 5 ). Fore wings; media coalescing 
with radius from base to beyond middle of wing, or coalescing 
with cubitus at base and passing obliquely to radius beyond 
R2+3J and anastomosing with radius to bejmnd middle of wing 
as before. R4 sometimes coincident with R5. Media single- 
branched. Cubitus usually reaching nearly to margin. Hind 
wings; media single-branched. 
As far as known the larvae of all of the North American species 
are miners within the tissues of leaves. The egg is placed on 
either the upper or under surface of the leaf, often along the side 
of a vein, and the larva passes directly into the interior of the 
leaf. The larva usually mines just beneath the upper epidermis, 
consuming the palisade layer of cells, and in later stages, some of 
the spongy parenchyma cells (Fig. 7 ). In thin leaves the mine 
seems more transparent, because of the originally smaller number 
of these cells and the looseness of their arrangement. Where the 
upper or lower surface is mined indiscriminately, as is the case 
with leaves of poplar by N. populeiorum, the cross-section of 
the leaf shows palisade cells on either side. Some species mine 
different sides of the leaf at different periods of larval life. The 
mine may be a linear tract, gradually increasing in breadth to its 
end, or it may at some point suddenly enlarge into a blotch. A 
change in the character of the mine usually indicates the begin- 
ning of a new instar. There are four larval instars. The mine 
formed during the first instar is very short, rarely exceeding a few 
millimeters in length. The large conspicious portion is made 
during the last larval instar in the few days preceding the escape 
