Agamic gen. of Neuroterus noxiosus (Bass.)

Stem galls.
NOXIOUS OAK GALL. Irregular woody enlargement at or near the ends of twigs on trees of Q. bicolor, up to 40 mm long by 25 mm in diameter, covered with normal bark, polythalamous, conspicuous on the trees in winter. The adults emerge in early April and oviposit in the buds just as they are beginning to swell.

Neuroterus noxiosus (Bass.)

Quercus bicolor, prinus
Stem galls, woody stem swellings
Agamic. Woody, covered with normal brown bark, persisting over winter.

[Photo caption]
Fig 121. Agamic. On Q. bicolor. The woody galls persist over winter. Adults emerged in April (IL) and were observed ovipositing in buds just as the bud scales elongate enough to show a little green at the base. Photo also shows the smooth fleshy galls of the alternating generation on the leaves.

Neuroterus noxiosus (Bassett)

The woody stem galls of the agamic generation are very conspicuous in winter on certain trees of Quercus bicolor at Evanston IL, the adults emerging April 10-14, April 1, and May 10. They were seen to oviposit in buds, thrusting the ovipositor perpendicularly through the bud scales just as the buds were beginning to swell. On July 22, the young stem galls of the winter form were half grown but still green and succulent with no larvae visible.

Neuroterus noxiosus form noxiosus

Galls. — Irregular, elongate, woody swellings (Figs. 17 to 19) of young stems and sometimes petioles. Polythalamous. About 60X10 mm., roughly cylindrical, but often very irregularly twisted, etc. Inseparable from the plant. Bark-colored, usually with a glaucous bloom. Internally the gall is closely packed with larval cells which are distinct but not separable from the surrounding woody tissue. On the newer growth of Quercus bicolor , Q. Prinus , and possibly other oaks.

Range: MA, RI, CT, NY, NJ, New Brunswick, IL, IO, MI

This gall is the better-known form of the species, due apparently to its longer persistence on the tree. The gall very closely resembles that of Neuroterus batatus batatus, from specimens of which it is often difficult to distinguish this species. The more highly distinct larval cells of noxiosus is often a good basis for making the distinction. The most certain test, however, is the species of the host plant, noxiosus being confined as far as known to Quercus bicolor and Q. Prinus , while batatus occurs on Q. alba. It would prove interesting to try to induce one of these species to oviposit on the “wrong” species of oak, and to observe if galls and what galls were produced. The larvae of noxiosus overwinter in the galls, emerging the following spring from March 24 through April to early May.

Cynips noxiosa, n. sp.

Galls: Large, woody, polythalamous, terminal or subterminal swellings on the twigs of Q. bicolor, varying greatly in size and form, but usually tuber-like and three or four times as long as thick. They larger specimens in my collection are nearly an inch in diameter and four inches long, and contain a large number of insects. The smallest are almost imperceptible swellings, and have often but a single insect. These galls develop in the summer, and the insects, which are all females, live in the galls over winter, coming out before the leaves appear in the spring. They resemble, both gall and gall-fly, C batata B, and I for a long time, considered them a variety of that species.

Neuroterus noxiosus Bass
Agamic form, noxiosus Bass

Gall, irregular, elongate woody swellings of young stems and sometimes petioles

Adults, late March to early May

On Q prinus [montana], bicolor

Neuroterus batatus variety noxiosus
agamic form noxiosus (Bassett)

Cynips noxiosa
Neuroterus noxiosus
Neuroterus noxiosa
Neuroterus consimilis [see ID Notes]
Neuroterus noxiosus form noxiosus

Gall.--As described for the species; large, woody, on stems of Quercus bicolor. This agamic gall begins to develop in mid-summer, the insects staying in the galls nine or ten months, emerging from March 24 to early May. Noxiosus has always heretofore been considered a distinct species, no one having pointed out the very close resemblance to batatus. If this is remembered it will help one to understand the distinctness of my other varieties. Noxiosus differs from batatus mainly in slight color characters, the slightly different shape of the abdomen, and the size of the areolet being the total of other differences. To be consistent, some workers should treat noxiosus as a complete synonym of batatus, which no one will do in the face of the patent loss of good host and life history data.

Range.--MA, RI, CT, NY, NJ, New Brunswick