66 ENTOMOLOGICAL SOCIETY 



panied with the consequent increase of wood-boring insects. 

 He strongly held that our cultivated trees are more vigorous 

 in growth than their natural congeners in the natural forest, 

 while the trees of North America, as a rule, grew more vigor 

 ously than those of Europe ; and that the view that insects 

 attack cultivated trees because these are more tender is en 

 tirely erroneous. 



Mr. Howard read the following paper : 



THE HABITS OF EURYTOMA. 



BY L. O. HOWARD. 



From the close morphological relationship of Eurytoma with 

 the only phytophagic chalcidid genus, Isosoma, it has been 

 questioned as to whether the former genus might not be in- 

 quilinous, or at least contain inquilinous species. From the 

 fact that Eurytoma is reared almost exclusively from the 

 habitations of endophytic insects, the correctness or incorrect 

 ness of this surmise is difficult to ascertain ; and while the 

 general opinion is to the effect that Eurytoma is parasitic, still 

 no conclusive observations concerning the gall-inhabiting 

 forms are on record, so far as I know ; and we must remember 

 that general opinion has always, until very recently, considered 

 Isosoma as a parasite, solely from a supposed necessary uni 

 formity of habit in the family Chalcididse, or the series 

 Parasitica. 



Eurytoma is reared commonly from hymenopterous (Cynipid 

 and Tenthredinid) and dipterous (Cecidomyiid, Trypetid and 

 Agromyzid) galls, as well as from the burrows in wood of 

 beetles of the families Curculionidse and Scolytidae, and of wood- 

 boring bees and wasps. But two exceptions to this general 

 statement are known to me. Mayr reared E. appendig aster 

 from a Microgaster cocoon, and Giraud reared E, nodularis 

 from a burrowing wasp's nest, and noted that it was hyperpar- 

 asitic upon Cryptus bimaculatus . 



In order to absolutely prove the actual habits of the species 

 so commonly reared from galls, it will be necessary to open a 

 gall at the proper time, note what the larvae are doing, and 

 watch them to maturity, and thus determine that you have 

 Eurytoma larvae and not those of some other of the very 

 numerous gall-inhabiting Chalcidids. 



Somewhat by accident, and certainly by good fortune, I 

 have just been able to accomplish this result : In August, 



