Neuroterus junctor, new species
bisexual form?

GALL.—Irregular, monothalamous or polythalamous swellings in the blade of the leaf, wholly inseparable, well developed on both surfaces of the leaf, though more developed on the under surface ; covered with a short but dense pubescence, each gall separable or more or less fused with other galls.

HOST.—Quercus texcocana [deserticola]

RANGE.—Mexico: Mexico City, 12 W, 8500' (types).

LIFE HISTORY.—Adults: March 15 (possibly of a bisexual, possibly of an agamic generation).

This insect provides an important link between two complexes which were recognized as related, but not understandably connected by the previously described American species. The first, the irregularis complex, is confined to the Eastern half of the United States. The second, Neuroterus decipiens, is a single species known only from California. The gall of junctor is very much like the galls of the irregularis complex, but the insect is closer to N. decipiens—in fact, closer than any species of the irregularis complex. It has been puzzling to understand how the Eastern American group, irregularis, could have a close relative, decipiens, in California, when neither group is represented in the Rocky Mountain area; but with this new species junctor as a clue, we shall direct our search into Mexico for the connecting links between the American complexes.

Since both irregularis and decipiens are known only from bisexual forms, it is quite possible that junctor represents a bisexual generation; but this is not determinable either from our limited material or from the collection and breeding dates with our series.