Kinsey: Studies of Cynipidx 



128 



with a distinct lining-, closely embedded in the less solid part of the tissue. 

 On black oaks. 



RANGE, — Arizona. Possibly also in New Mexico, western Texas, 

 and Mexico, wherever Q. Emoryi, Q. hypoleuca, and related oaks occur. 



The insect of this species is in several respects, particu- 

 larly the almost naked mesonotum and the 14-segmented, 

 short antennse, extreme for this genus. But species like P. 

 suttonii and P. perdens of California are intermediate between 

 coxii and the white oak species of the genus. This empha- 

 sizes the artificial nature of our sharp generic lines. I doubt 

 whether I should consider the species in this genus except for 

 the additional evidence furnished by the gall. It is typically 

 a Plcigiotrichus gall, related more closely to the other black 

 oak species, as is the insect also, than to any other white oak 

 species. 



The insects emerge in midwinter, December and January. 

 The young galls appear immediately, which suggests that they 

 arise from an alternate generation, the whole life cycle taking 

 more than one year. 



I have galls from New Mexico which may belong to this 

 species, but rather extensive collecting in both western Texas 

 and New Mexico failed to give me other galls of this species. 

 If the species occurs in those states, it certainly does not there 

 reach the abundance with which it infests the black oaks of 

 southern Arizona. 



Plagiotrichus coxii variety coxii (Bassett) 



Cijnips Coxii Bassett, 1881, Can. Ent., XIII, p. 112. 



Cynips coxii Packard, 1881, U.S. Ent. Comm. Bull., VII, p. 57. 



Andnc2is Coxii Ashmead, 1885, Trans. Amer. Ent. Soc, XII, pp. 295, 



304; 1887, Trans. Amer. Ent. Soc, XIV, p. 132. Ashmead (in 



Packard), 1890, 5th Rpt. U.S. Ent. Comm., pp. 106, 110. 

 Andricus coxii Dalla Torre, 1893, Cat. Hymen., Cynip., II, p. 84. Dalla 



Torre and Kietfer, 1902, Gen. Ins. Hymen. Cynip., p. 62; 1910, Das 



Tierreich, XXIV, pp. 530, 801, 825. Beutenmuller, 1907, Bull. Amer. 



Mus. Nat. Hist., XXIII, p. 465. Thompson, 1915, Amer. Ins. Galls, 



pp. 6, 31. Felt, 1918, N.Y. Mus. Bull., 200, p. 58. 

 Andricus Coxii Bassett, 1900, Trans. Amer. Ent. Soc, XXVI, p. 320. 

 Andricus Bassettianus Dalla Torre and Kieffer, 1902, Gen. Ins. Hymen. 



Cynip., p. 61. 



AndHcus bassettianus Dalla Torre and Kieffer, 1910, Das Tierreich, 

 XXIV, pp. 532, 802, 838. 



FEMALE. — Differs from the female of variety translatus as fol- 

 lows: Two basal segments of the antennse rather dark brownish rufous, 



