1899] ENTOMOLOGICAL NEWS. 193 



l-J. C. Ridinssii Bland, Tenn. 



13. < 'reniHstorhilus leuro^tirtiis Burin, male. 



14. Crernastocbilus leucost ictus Burin, female. 



O 



THE, LARGEST OAK-GALL IN THL WORLD AND ITS PAR- 



ASITES. 



BY WILLIAM H. ASH MEAD. 



Some two or more years ago, February 20, 1897, the Na- 

 tional Museum received from Dr. A. Duges, of Guauajaro, 

 Mexico, the largest oak-gall it has ever beeu my pleasure to 

 see, and which is undoubtedly the largest Cyuipid gall yet 

 discovered. Subsequently additional specimens of the same 

 species, but much smaller and exceedingly variable in shape 

 and size, were also received from Dr. Duges. 



The first and largest specimen received, and which is un- 

 questionably the largest oak-gall in the world, is of an irregu- 

 lar oblong, globular shape, and measures fully 4J inches long 

 by 3 inches in diameter. Externally it is opague, more or 

 less roughened, and of a greyish color or somewhat similar in 

 color to the bark of our common white oak ; white internally it 

 is brown and of a dense, hard, pithy substance. It is polytha- 

 lamous ; the larvae cells being numerous and deeply imbedded, 

 in the interior of the gall, as in those of similar structure. 



The other specimens, afterwards received from Dr. Duges. 

 are, as stated before, much smaller, more irregular in shape, 

 and dwindle down in size to specimens not exceeding an inch 

 in diameter. All of them, as we are reliably informed by Dr. 

 Duges, were obtained from the roots of an unknown Mexican 

 oak tree. 



At the time of the receipt of the largest of these galls, I re- 

 ported the gall was the product of an undescribed Cynipid, 

 which would probably prove to belong to the genus Andri- 

 cus. 



The rearing of three of the gall-flies by Dr. Duges con- 

 firms my opinion in reference to the generic position of the 

 gall -makers of this gigantic gall, but the gallitself is evidently 

 similar to one described as (\i/ni)>N Clutinjtiotii by Mr. Peter 

 Cameron, in Biologia Central!- Americana, Hymoptera, vol. 1, 

 p. 70, the maker of which was unknown. 



Dr. Duges also bred from this gall two distinct parasites: 

 ;t Miquiline, Si/n rr/iix sp., and a Toryiuid, Tori/nntx sp.; also M 



