xii Introduction. 



inquilines and parasites under the genus Cynips, indeed 

 St, Hilaire, Latreille, and Olivier reserve the name 

 Cynips for certain Chalcididae, and use Diplolepis for 

 the true gall-maker, but with few exceptions subsequent 

 writers have applied the general name Cynips to the 

 gall-makers. It is well, however, to bear this change of 

 nomenclature in mind, when the males of certain species 

 are said to have been found \ Reaumur has left 

 excellent descriptions and drawings of many species of 

 galls ", but the first to bring order out of the confusion 

 in which the Cynipidae still remained, was Theodor 

 von Hartig of Brunswick ^ He greatly improved the 

 existing classification of this family and carefully pointed 

 out the true relationship which the various dwellers in 

 galls bore to each other. He arranged gall inhabitants 

 into three classes ; first, the gall-makers which he com- 

 pared to the actual householders ; secondly, inquilines, 

 guest-flies, cuckoo-flies or lodgers, who take up their 

 quarters uninvited within the gall, and live on its food 

 stores, but do not directly aim at the gall-maker's life ; 

 and thirdly, parasites who deposit their eggs on the 

 larvae of their host or his lodgers, with the object of 

 destro3^ing them, and who are therefore murderers. 

 Besides those living in a state of symbiosis, there are 

 also true commensals in some galls. 



It is the simultaneous presence of these various classes 

 that frequently gives rise to confusion in carrying out 

 breeding experiments. Synergi among inquilines re- 

 semble true gall-making species so closeh^, that caution 



^ Westwood, Zoological Journal, No. 13 ; Cameron, P., British 

 Phyt. Hymen, vol, iii, p. 140. 



- Reaumur, Memoires pour servir d Vhistoire des insecfes, 

 1734-42. 



" Hartig, 'Ueber die Familien der Gallwespen,' Germar^s Zettschr. 

 f. d. Eni. II. Heft i, p. 176, 1840; III. 322-358, 1841 ; IV, 395, 1843. 



