112 FIFTH REPORT OF THE ENTOMOLOGICAL COMMISSION. 



length; producing sometimes a black gall-fly with tawnj-red legs and the second 

 veinlet of its wings elbowed or angularly bent backwards, its length .15; sometimes 

 a smaller fly (C. oneratus) of a clear pale yellow color, almost white, with a broad 

 black stripe the whole length of its back, which color in the males is more extended, 

 reaching down upon the sides, its length .12. (Fitch,) 



These species are parasitized by two chalcid flies, Macroglems querci- 

 glohuli Fitch and Pteromalus onerati Fitch. 



The wool-sower gall-fly. 



Cynips seminator Harris. 



Order Hymenoptera; family Cynipid^. 



A round mass resembling wool, from the size of a walnut to that of a goose egg, 

 growing on the side of or surrounding white-oak twigs in June, of a pure white color, 

 or tinged or speckled with rose-red, and in autumn the color of sponge; producing 

 small shining black gall-flies with bright tawny yellow legs and antennae, and in the 

 female the head and thorax cinnamon-red; their antennae of fifteen and fourteen 

 joints; length .08, and females .11 inch. (Fitch.) 



The oak-tumor gall-fly. 



Cynips guercus-tuber Fitch. 



Order Hymenoptera; Family Cynipid^. 



On or near the ends of the small limbs and twigs of the white oak, hard irregular 

 swellings thrice as thick as the twig below them, the bark upon them of a brighter 

 cherry -red color than elsewhere, and their substance internally corky and woody; 

 produced by the stings of a small black gall-fly, with dull pale yellow antennae, mouth, 

 and legs, its hind shanks and its antennae towards their tips being dusky, its length 

 .08 and to the tips of its wings .13. (Fitch.) 



The oak-tree gall-fly. 



Cynips quercits-arbos Fitch. 



Order Hymenoptera; family Cynipid^e. 



Swellings similar to those above described, growing on the tips of the limbs of aged 

 and large white-oak trees ; producing a small black gall-fly having all its legs and 

 antennae of a bright pale yellow color, and one more joint in the latter organs than 

 in the preceding species in the males, which sex is .06 in length, and to the tips of 

 its wings .10. (Fitch.) 



The following observations are from Professor Riley's unpublished 

 notes : 



Cynips quercns-seminator Harris. 



Galls of this species were found on twigs of Q. alba in May and June in Virginia, 

 and the flies and several species of Chalcidians issued from them. 



The Cynipids are the true sexes, and were issuing June 13, and the parasites, among 

 which was also a Cecidomyid, issuing from June till November 12. 



Many of the galls were placed with a small tree of Q. alba and covered with gauze 

 for observation, but notwithstanding the great number of flies, not a single gall was 

 produced on leaves or twigs. 



