NOTES ON AMEEICAN GALLFLIES OF THE FAMILY 



CYNIPIDAE PRODUCING GALLS ON ACORNS, WITH 



DESCRIPTIONS OF NEW SPECIES. 



By Lewis H. Weld, 



Of the Bureau of Entomology, United States Department of Agriculture. 



Only 8 American acorn galls have hitherto been described. The 

 present paper gives descriptions of 12 new species, together with a 

 synopsis of the galls and keys for the determination of the adults. It 

 was prepared under the general supervision of Mr. S. A. Rohwer, 

 Specialist in Forest Entomology, to whom acknowledgment is due for 

 access to the material and records in the Division of Forest Insects, 

 Bureau of Entomology. 



Types of the new species have been deposited in the United States 

 National Museum and paratypes and balsam mounts are with the 

 author. Where sufficient material is at hand paratypes are available 

 for exchange with other institutions for species not in the National 

 Collection. 



The author has field notes on some 36 other acorn galls not here in- 

 cluded because adults have not as yet been reared. If systematic 

 search were made, especially in early spring and in the autumn, no 

 doubt still other species would be found not only in the eastern region, 

 where most collecting has been done, but especially in the remoter 

 parts of the country and on the more local species of oak. Acorn 

 galls do not often occur in large numbers and are overlooked by the 

 casual observer, but one is often guided to the smaller ones by noticing 

 ants and wasps attracted by the secretion of honeydew. They are 

 difficult to rear, as many require at least two seasons and meanwhile 

 must be kept in a normal environment. Some form of wire breeding 

 cage which can be kept out of doors on the groimd will answer this 

 purpose. The alternating generation in one instance is known to be 

 a flower gall, and much work might be done on the biology of this 

 group. From the above it will be seen that having reared the adults 

 from an acorn gall the chances are almost two to one that it can not 



No. 2440-Proceedings U. S. National Museum. Vol. 61. Art. 19. 



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