British Ichneumonidcp, Braconidce, Sfc. 261 



formlty of appearance. And this of course is the only- 

 excuse for those tiresome and petty operations in which 



" A's deposed, and B with pomp restored." 



With regard to the arrangement of species, the cata- 

 loguer would gladly have placed the typical species of each 

 genus first, and the rest in the order of their affinity to 

 that type. But the imperfect condition of the literature 

 relating to these insects, the absence of definitely consti- 

 tuted types, and the impropriety of setting up any freshly 

 selected according to apj^earances, forbade the uniform 

 application of this principle. For one reason or another, 

 the ado])tion of any fixed principle throughout was equally 

 impracticable, except that of alphabetical arrangement. 

 This is so far from being any real system, that it is rather 

 a confession of the utter absence of system, and moreover 

 its adoption in this case would have been retrogression, by 

 losing sight of such partial arrangements as have been 

 here and there already proposed. In this difficulty then 

 the cataloguer has been guided by Avhat he conceived to 

 be the highest principle ai^plicable to each particular case, 

 resorting, where that failed, to the next lower principle, 

 and, as a last resource, betaking himself to alphabetical 

 arrangement. Wherever this may be found to prevail, it 

 must be taken to indicate the impossibility, from want of 

 knowledge, of effecting a more satisfactory arrangement ; 

 ex. gr. Ichneumon, spp. 109 — 144, Tryphon, Mesole-ptus, 

 and Limneria. 



The order of sequence in the synonyms is the same as 

 that adopted in the Catalogue of Neuroptera, and which 

 differs somewhat from that of the Aculeata. The choice 

 of these citations, most numerous and perplexing, pre- 

 sented several difficulties not AvhoUy to be overcome, and 

 only to be mitigated by the exercise of a free discretion. 

 It will be seen that of the mass of references given by 

 Gravenhorst, a considerable number are omitted. They 

 are, as a rule, dubious in different degrees, and their 

 introduction would have greatly increased the size of the 

 Catalogue, while at the same time they diminished its use- 

 fulness. The degree of similarity which many years ago 

 was sufficient to satisfy entomologists of the identity of two 

 insects, would not content the more minute observers of 

 the present day. Without attempting then to prescribe 

 for himself any strict rules for action in a matter requiring 

 T 2 



