108 ENTOMOLOGICAL SOCIETY 



in each puparium, all of the parasites which have issued (and 

 there are as many as nine in some cases) having utilized the 

 orifice made by one hard-working individual. 



The extended list which follows (extended in view of the 

 paucity of our previous knowledge) Dr. Riley has permitted 

 me to draw up from the National Museum collection, recently 

 rearranged at his direction by Mr. Ashmead, and it is safe to 

 say that there nowhere exists a collection of Microhymenoptera 

 which exhibits such a wealth of bred forms. Collected speci 

 mens are also present which, from their labels, indicate that 

 the species fly from February to October, while such notes as 

 are at hand indicate that they are rapid breeders. 



THE HOST-INSECTS OF PACHYNEURON IN THE UNITED 



STATES. 



ON PSYWJD^. 



Pachyneuron sp. From Psyllid on Arbutus (undetermined) ; reared by 

 Koebele, at San Mateo, Cal. 



ON COCCID^). 



Pachyneuron altiscuta Howard. From Coccid on Blue Ash ; reared by 



A. J. Cook, at Agricultural College, Mich. 

 Pachyneuron sp. From Kermes gall&formis Riley ; reared at Washing 



ton, D. C. 

 Pachyneuron sp. From Dactylopius citri Boisd. ; reared at Washington, 



D. C. 



ON 



Pachyneuron sp. From Aphis pruni ; reared by H. Osborn, at Ames, 



Iowa. 

 Pachyneuron sp. From Siphonophora viticola ; reared at Washington, 



D. C. 

 Pachyneuron micans Howard. From Siphonophora avencs ; reared at 



Lafayette, Ind., by Webster. 

 Pachyneuron micans Howard. From Toxoptera graminum, from Ten 



nessee ; reared at Washington, D. C. 

 Pachyneuron aphidivora Ashmead. From Aphis brassicce; reared by 



Ashmead at Jacksonville, Fla. 

 Pachyneuron sp. From Chaitophorus on Populus ; reared at Washing 



ton, D. C. 

 Pachyneuron sp. From Phylloxera vastatrix (leaf-galls) ; reared at 



Washington, D. C. (Specimens collected across the Potomac in 



Virginia). 



