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Indiana University Studies 



GALL. — Rather similar to galls of the other varieties; elongate, 

 slender, regular, up to 14. mm. in diameter and 40. mm. long, usually 

 more slender; internally woody, with somewhat of a cavity, the larval 

 cells densely clustered and packed so closely sometimes (in one specimen 

 especially) as to exclude wood in much of the gall. On Qiiercus gar- 

 ryana. 



RANGE. — Oregon: Ashland, Grants Pass, Junction City. Probably 

 California to British Columbia, wherever Q. garryana occurs. 



TYPES. — 4 females, 4 galls. Holotype female, paratype gall at 

 The American Museum of Natural History; paratype females and galls 

 v/ith the author. Labelled Ashland, Oregon; April 6, 1920; Q. garryana; 

 Kinsey collector. 



Most of the insects had emerged before collection at Ash- 

 land on April 6; all of them had emerged before April 7 at 

 Grants Pass. 



This insect is to be distinguished by the darker color, the 

 more or less complete median groove, and small areolet. In 

 its general color and the shape of the abdomen, it resembles 

 pugniis, but in the smoother mesopleurse, less hairy abdomen, 

 and somewhat discontinuous cubitus it tends toward kelloggi 

 and diminuens. One cannot believe that it is necessarily orig- 

 inated from either group rather than from a more remote, 

 common ancestor. Host isolation in this case is accompanied 

 by geographic isolation, the combined forces offering splendid 

 opportunity for the development of a distinct form. 



Plagiotrichiis coxii (Bassett) 



FEMALE. — Shows the following characters in addition to those com- 

 mon to all species of the genus: Color rufous, in large part shaded to 

 black, usually solid black on the abdomen; antenna with 14 segments, 

 with the apical half brown, the basal half brownish rufous; mesonotum 

 relatively smooth, mostly finely reticulated or shagreened, entirely smooth 

 betAveen the anterior parallel lines, very sparsely hairy, most hairy on 

 the scutellum and antero-laterally ; parapsidal grooves continuous, nar- 

 row: median groove short or lacking; fove« rather large, distinct, but 

 separated by only a fine I'idge; mesopleurse smooth, shining, naked, a 

 transverse, medial band finely shagreened; abdomen black, smooth, not 

 reticulated, but the posterior segments finely punctate, mostly naked 

 except for a few hairs latero-basally ; as long as high, the second seg- 

 ment covering slightly more than half the area; legs rich rufous and 

 brown, the coxse dark; cubitus complete or just short of being complete; 

 length 2.2-3.0 mm. 



GALL. — A globose to elongate, solid twig gall. Polythalamous, 

 averaging twenty or more cells to a gall. Smooth, covered with nearly 

 normal bark, somewhat reddened; up to 20. mm. in diameter and 65. mm. 

 in length. Internally rather solid but not entirely so, the larval cells 



