24 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 61. 



tional Museum has six pinned flies bearing Riley's label "467, April 

 5, 1873, Acorn pip gall." These are the original flies reared by 

 Riley nearly 20 months after the galls Avere collected, and Riley's 

 original notes are on file in the Bureau under U. S. D. A. No. 467. 

 They represent the alternating generation of operator and established 

 the alternation of generations in the Cynipidae, They range from 

 3.1-3.9 mm. Average 3.3 mm. Two others in balsam give the fol- 

 lowing ratios, using width of head as a base : Length of mesonotum 

 1.2, 1.23 ; antenna 2.04, 2.03 ; ovipositor 3.02, 3.01 ; wing 3.59, 3.68. 

 Some of these reared flies were submitted (July 10, 1873, says Kin- 

 sey) to Bassett to be compared with flies Bassett had taken ovi- 

 positing in buds of ilidfoUa on May 4, 1873. They seemed to Bassett 

 to agree v.ith his and probably were returned to Riley again. In the 

 United States National Museum are two flies labeled in Bassett's 

 hand and sent by Bassett to Ashmead ''''Andncus {C allirhytis) op- 

 eratola Riley. The one-gendered form of operator taken oviposit- 

 ing in buds of Q. iVicifoliaP They measure 3.25 and 3.75 mm. They 

 seem to the writer to agree with the flies Riley reared. 



In writing of the species over a quarter of a century later, however, 

 Bassett was in error in saying that Riley had reared and sent him flies 

 the next sj^ring, and the long period of development of the agamic 

 as compared with the sexual generation seems to have made little 

 impression. The agamic flies preserved in Philadelphia as the types 

 of this species seem to the writer to represent two species — two speci- 

 mens agreeing with those in the United States National Museum and 

 with those Riley reared. Among the duplicates there was a vial 

 determined by Bassett as this species, containing 11 specimens. These 

 the writer obtained permission to mount. They were taken oviposit- 

 ing in buds April 24, 1892. Six of these seem to be the agamic form of 

 operator. 



In Avriting of the life history of this species Kinsey is in error in 

 stating that the sexual females oviposit in June in the " very small, 

 young acorns." There are two kinds of young acorns on the tree 

 at that date and it is the 1-year-old acorns that are attacked. The 

 writer lias seen them ovipositing in these immature acorns on June 

 30, 1909, at Miller, Indiana. These acorns are at that date about 

 8 mm. in diameter and almost entirely inclosed in the nearly spheri- 

 cal cup with only the stigmas protruding. The female backs up 

 toward the stigma, slipping the ovipositor dow^n between acorn and 

 cup. The galls occur then in acorns of the current j^ear's crop and 

 mature earlier than is popularly supposed, being full grown and 

 beginning to drop at Ithaca, New York, late in July. The base of 

 the gall becomes delequescent and the normal gall slips out, where 

 its outer layers soon disintegrate, leaving but the transversely placed 

 thin white inner cell. If parasitized, however, they remain and fall 



