Neuroterus niger Gillette, 1888

Neuroterus vernus Gillette, 1889, sexual generation, syn. nov.

Material examined. Five asexual females labelled as “CANADA: Alberta, Edmonton, Grand Trunk Pool, SC30, 2002.04.12. S. Digweed, Neuroterus niger Gillette females of the asexual generation, det. S. Digweed 2005”. Sexual generation: 5 females labelled as “CANADA, Alberta, Edmonton. Reared 18.iv.2005, ex Q. macrocarpa. N. niger (?) gall, Grand Trunk, coll.22.ix.04. S. Digweed”; 5 males labelled as “CANADA, Alberta, Edmonton. Reared 3-13.x.2005, ex Q. macrocarpa. N. niger (?) gall, Grand Trunk, coll.22.ix.04. S. Digweed”.

Gall. The sexual generation galls (Fig. 182), first recorded as N. vernus, are cells hidden within new shoots, on the young leaf petioles and midribs and on the catkins of Q. macrocarpa; these plant organs are sometimes distorted as a result (Digweed 2010).

Biology. Galls of the sexual generation are on Q. alba, Q. bicolor and Q. macrocarpa (Gillette 1890, Burks 1979, Digweed 2010). We observed that clusters of galls (e.g., on one catkin) often produced adults of only one gender. Galls were visible in Edmonton in May, with adults emerging in late May or early June. Sexual generation females were observed ovipositing mostly on the undersides of leaves and often on leaves that were on long shoots and/or that were not yet fully mature.

Distribution. In the USA the asexual generation has been recorded from Massachusetts, Michigan, Wisconsin, Iowa (Burks 1979), Illinois, Indiana, New York, New Jersey, Pennsylvania, Ohio (Beutenmueller 1910); Arizona, Texas (Kinsey 1923), and Alberta and Manitoba in Canada. The sexual generation has been recorded from Illinois (Weld 1926), Iowa (Burks 1979), and TX (Kinsey 1923) in the USA and Alberta in Canada.

Neuroterus vernus

Quercus macrocarpa
Leaf galls, integral
Swollen petioles dwarfed and deformed on young leaves. Type host. Adults May 16- June 10. Entered from lit.

Neuroterus vernus

The writer has found galls of this species only once, and at Moline, IL. The adults had all emerged before July 21.

Neuroterus vernus variety vernus bisexual form

GALL. — A slight, irregular swelling of ament stems, young leaf veins, or petioles; on Quercus macrocarpa.

RANGE. — Iowa: Ames (Gillette). Illinois: Algonquin (Nason). Probably confined to an area in the Middle West.

Gillette stated that this insect was '‘double brooded’', but failed to distinguish agamic and bisexual forms, not obtaining the male. He noted that the insects of the two generations differ somewhat in color. He stated that the one (agamic) generation emerged in April, the bisexual in May and June. The agamic galls are confined to leaves. I have not seen material, and draw the descriptions from Gillette’s original accounts,