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 from the rest of the plant. Bark-colored, reddish, purplish brown, or with a glaucous bloom. Internally the galls are solid, woody, the larval cells scattered irregularly, the cell walls hardly distinct and not at all separable from the surrounding tissues. On terminal stems of Quercus alba (not known definitely from any other species of oak).

.—Bassett morphotype females and galls in the collections of The American Museum of Natural History, the Museum of Comparative Zoology, and of the Academy of Natural Sciences of Philadelphia, and Fitch cotype galls in the Museum of Comparative Zoology.

The galls of this generation, because they remain upon the tree for the longer time and often reach the larger size, are the better-known of the two forms of this species. The insects live in the galls over winter, emerging late the following April or early in May.

The very great similarity of the adults of the two generations of this species (except for the agamy in the winter generation) and the essentially identical plan of the galls of the two forms, is a matter of great interest. In this species, as in Neuroterus noxiosus, we find as simple a case of alternation of generations as has yet been recognized. The differences in the galls are very evidently due to seasonal differences of the conditions in the part of the host affected.

Neuroterus noxiosus (Bassett)

In most of the following references both generations, at least of the gall, are described separately.

[No name], 1873, Can. Ent., V, p. 92; Trans. Ent. Soc. Lond., p. xv.

Cynips noxiosa, 1881, Can. Ent., XIII, p. 108. , 1881, U. S. Ent. Comm. Bull., VII, p. 57.

Neuroterus noxiosus, 1881, Gen. Gallenbew. Cynip., p. 37. , 1882, Amer. Nat., XVI, p. 246. , 1885, Trans. Amer. Ent. Soc., XII, pp. 296, 303. , 1888, 27th Report Agric. Mich., p. 471; 1889, Psyche, V, p. 187. , 1890, 5th Report, U. S. Ent. Comm., pp. 107, 109. , 1892, Bull. Amer. Mus. Nat. Hist., IV, p. 262; 1904, Amer. Mus. Journ., IV, p. 107, fig. 42; 1904, Bull. Amer. Mus. Nat. Hist., XX, p. 27; 1904, Amer. Mus. Nat. Hist. Guide Leaf. 16, p. 21, fig.; 1910, Bull. Amer. Mus. Nat. Hist.; XXVIII, p. 118, P1. ix. , 1893, Cat. Hymen., II, p. 44. , 1902, Gen. Ins., Hymen., Cynip., p. 51; 1910, Das Tierreich, XXIV, p. 330. , 1906, Ins. Aff. Pk. & Wood]. Trees, II, pp. 618, 624, 711; 1918, N. Y. State Mus. Bull., CC, pp. 58, 84, fig. 55. , 1906, Ent. News, XVII, p. 8., 1910, Springfield (Mass.) Mus. Bull., II, p. 30. , 1910, Ins. N. J., p. 598. , 1910, Mich. Geol. & Biol. Surv. Publ. 1, p. 30. , 1915, Cat. Amer. Ins. Galls, pp.6,13,41, P1. iv, fig.118 [not Pl. I, fig. 16]. , 1916, Hymen. Conn., p. 391. , 1918, Field Book Ins.,p. 464, P1. XCVIII, fig. 11.

Neuroterus noxiosa, 1887, Trans. Amer. Ent. Soc., XIV, p. 132.

.—Massachusetts: Everett (Clarke); Boston; Amherst (Thompson); Springfield (Stebbins); Marthas Vineyard. Rhode Island: Providence (Thompson).