form of the plant, monspeliensis, which ranges from Alaska south into the District of Columbia and New Mexico. Or possibly still others of the larger-stemmed, shrubby species of Potentilla will have the same gall.
I also cut a parasite out of the gall—a species of Eurytomidæ.
Neuroterus thompsoni, new species
Plate XXI, Figures 8 and 9
Neuroterus rileyi [error] Thompson, 1915, Cat. Amer. Ins. Galls, p. 7, P1. in, fig. 173.
Female.-Almost entirely black, the antennæ ringed with light yellow at the second to third joint; length under 2.0 mm. Head: black, mouth-parts reddish brown; antennæ 13-jointed (inclined to curl in dried specimens), joints one and two stouter than the following joints though not as globose as in most species of Neuroterus, first joint dark brown, part of the second joint and the proximal tip of the third joint very light yellow, joints three to thirteen dusky brown-black. Thorax: piceous black; mesonotum microscopically cracked, without grooves; sides of the thorax lighter reddish black. Abdomen: piceous black, subpedicellate, rather angulate in outline; ovipositor apparently short. Legs: light brownish yellow, the hind femora and tibiae dusky brown except at the joints; tarsal claws almost black. Wings: veins brown, the cubitus reaching the basal vein below the midpoint, the areolet rather large, the radial cell long, narrow, open. Length: 1.7 mm.
Male.—Differing from the female as follows: antennæ 14-jointed, uniformly yellowish; thorax reddish amber; abdomen elongate, pedicellate, yellowish brown, pedicel light yellow; legs uniformly yellow but with the tarsal claws black; length, 1.7 mm.
Galls.—Pustulate swellings under the bark (Figs. 8 and 9), each swelling oval, about 2 × 3 mm., and elevating the bark about 1.0 mm.; usually many galls are confluent, around the twig and along it for a length of 2–12 cm. Larval cells, distinct but inseparable, lie in the wood, near the bark, 1–5 to each pustule, and each about 0.7 mm. in diameter. On young twigs of Quercus prinoides.
Range.—Massachusetts (M. T. Thompson Coll.).
Cotypes.—Twenty-three females, two males, and 6 galls, distributed in the collections of The American Museum of Natural History, the Boston Society of Natural History, of Mr. W. T. Davis, and in the author's collection.
The galls form in May.
Dr. M. T. Thompson mistook this material for Neuroterus rileyi, a middle-western species which N. thompsoni in general resembles, but the two are really quite distinct. N. thompsoni is only about half as large as the other species, both in the gall and the adult; the coloring of the antennæ and legs will distinguish thompsoni.
Through the kindness of Mr. C. W. Johnson, Curator at the Boston Society of Natural History, I have had an opportunity to study cynipid material in the Thompson Collection of galls and gall-insects. Though this collection was made in but a single season, the number of species therein represented is surprisingly large and is a credit to the thoroughness with which Dr. Thompson worked. I am glad to be able to give his
