342 [Mat 



agaiuous Gynips Hartig invariably is. The presumption is. therefore, 

 that it belongs to a different genus, and this is supported, by the other 

 characters, as the sculpture, the shape of the abdomen, etc. Now G 

 scitula Bassett. known in both sexes, resembles G. punctata very much, 

 except that it is much smaller ; it occurs, like G. podagrse on Q. tinc- 

 toria, and produces a gall which, judging by the description, is not 

 unlike that of the latter species. These facts irresistibly suggest the 

 impression that G. podagrse, its larger size notwithstanding, is but an 

 a famous female of G. scitula. Again a fact for observers to investigate. 

 The above remarks may be summed up as follows: — 



1. The species of Gynips producing galls on trees of the white and 

 chestnut oakgroup ( tj. obtusiloba macrocarpa, (dim. prinu*, prinoides, 

 castanea, forming Mr. Gray's first division, fruit ripening the first year ; 

 compare dray's Manual of Botany,) seem to be. as a general rule, geue- 

 rically distinct from the species, producing galls on the trees of the 

 black, red and willow oak group ( ( t >. rubra . coccinea, tinctoria, falcata, 

 ilicifolia, palustris, phellos, imbricaria, nigra; dray's second division. 

 fruit not maturing until tin second year). Thus the genera Gynips 

 (in llartig's sense), Andricus, Spathegaster, Teras, as far as they are 

 recognized among the X. A. species, all occur on the white oak group, 

 whereas most of the species belonging to the other group will probably 

 require the establishment of new genera. Ilenee, the relationship with 

 the European fauna is especially to be found in the first group, the 

 second principally containing forms peculiar to America. 



2. If any species of Cynips produces galls on more than one kind of 

 oak it will always confine itself to oaks of the same botanical group. I 

 am not aware of a single exception to this rule.* 



Genus CYNIPS. 

 (Galls on trees of the genus Quercus.) 

 The number of species of Gynips in its present acceptation being 

 now more than forty, and a number of galls having been described be- 

 sides, the gall-flies of which are as yet unknown, it became very desira- 

 ble to have a general synopsis of the knowledge thus accumulated, the 

 more so as the data respecting this knowledge are scattered in several 

 volumes. To this end. the following two tables have been prepared : 

 1st. an analytical table of the known species of X. A. Gynips ; 2d. a 

 synoptical table of the known X. A. oak-galls produced or supposed to 



■ This was already written when I received Mr. Walsh's paper " On the in- 

 sects etc. inhabiting the galls of certain willows," (Proc. Ent. Soc. Vol. Ill, p. 543) 

 and found, that by a remarkable coincidence, this author has made precisely 

 the same observation (1. c. p. 639). 



