Kinsey: SUidies of Cyniiyidse 



21 



scattered or in small clusters, mostly toward the center of the gall, are 

 the seed-like capsules with the closely imbedded larval cells, each cap- 

 sule hard, oval, about 1.5 by 3.0 mm., sometimes 150 or more cells in a 

 gall. On or involving young stems, new clusters of leaves, and especially 

 the flower clusters. 



Agamic Generation : The larval cell occupying most of a triangulate 

 or obconical capsule, somewhat compressed, up to 5. by 4. mm. in dimen- 

 sions, one to six, usually one, between the nut and the cup of the acorn; 

 on all of the black oaks Avhich bear the bisexual generation. 



RANGE. — Ottawa to Virginia, Texas, and Illinois. Probably thru- 

 out more eastern North America wherever black oaks occur. 



The varieties I treat for this species are on a whole more 

 nearly related than are the varieties of most Cynipidse. There 

 is enough individual variation to make it difficult to definitely 

 determine every individual. Nevertheless series of each va- 

 riety average rather differently, and material of any variety 

 from separated localities agrees well in its characters. 



My first examinations happened to involve material from 

 several oaks, each oak from a different locality. I should 

 have believed the variation in the insects was due to their 

 isolation upon distinct hosts. But three different hosts at 

 Rosslyn, Virginia, give the same insect. The objections to 

 believing each variety restricted to a distinct faunal area are 

 that I have two varieties from Rosslyn, and that the ranges 

 as far as knovai are intricately connected, at least for three 

 of the varieties. HoAvever I rather expect to find that each 

 variety is restricted to a geologically distinct area. Our rec- 

 ords are still so few that it is quite possible my present inter- 

 pretations of this species Avill need revision, but I hope that 

 the facts have been so distinguished from my hypotheses that 

 others may be able to build on my work. 



This species is famous as the first for which an alterna- 

 tion of generations was proved. One generation occurs in 

 large, woolly galls, is bisexual, appears early in the spring, 

 and matures within a couple of months or less. The sexes 

 are probably produced in about equal numbers ; of 898 insects 

 of all varieties which we have bred, 447, or just about 50 

 per cent, are males. These data are not wholly significant, 

 however, because sometimes only a single sex is produced in 

 each gall. Patterson found this for a gall of austrior, and 

 collections of other varieties in several museums usually pre- 

 sent only one sex. Unless a considerable number of galls are 

 used for breeding, the sexes may be obtained in unequal num- 



