26 WHEELER— THE PARASITIC ACULEATA. 



among the parasitic ants. The Hst of the species in the table (Table 

 VI.) shows that they all belong to a single subfamily, the Myrmi- 

 cinae, and, with the exception of Hagioxcniis, to genera differing 

 from though allied to their hosts. 



The tables IV. to VI. are much more striking as illustrations of 

 the natural affinities of the parasites to their respective hosts than 

 the table of the bees (Table I.). This is undoubtedly due partly 

 to the fact that the ant-parasites are structurally much less sharply 

 distinguishable from their hosts and partly to the different views of 

 myrmecologists and melittologists concerning the scope and dignity 

 of the genus as a taxonomic category. The myrmecologist is being 

 so constantly impressed with the great structural variations that 

 may exist in the same colony of ants and often therefore among the 

 offspring of the same mother, that he is apt to be a " lumper" with 

 a vengeance, whereas the melittologist, especially on our radical and 

 progressive American continent, seems to develop a veritable pas- 

 sion for erecting new genera or even subfamilies on very minute 

 morphological characters. Thus Ashmead created a family Psithy- 

 ridse and Cockerell a subfamily Psithyrinse for the bees of the single 

 genus Psithyrus, although no one doubts that these insects are very 

 closely related to Bomb us, whereas no myrmecologist has dreamed 

 of placing the a.herrsint,worker\esspsLva.s\te Anergatcs atratulus even 

 in a distinct subfamily, although it differs much more profoundly 

 from Tetramorium and other Myrmicine genera than Psithyrus 

 from Bombus. No melittologist, moreover, ever thinks of placing 

 a new parasitic bee in one of the known genera of recoltant bees, 

 because the absence of the collecting apparatus is tacitly assumed 

 to have decided generic or even subfamily value, but among the 

 ants there are several genera ( Formica , Lasius, Aphccnogastcr, Crc- 

 matogaster, Lcptothorax) which are made to include both parasitic 

 and nonparasitic species, because there are no morphological char- 

 acters by which they can be satisfactorily distinguished. - 



Leaving out of consideration the guest ants, the origin of which, 

 as we have seen, can be accounted for in the same way as the myr- 



2 Forel has, indeed, placed Formica sangtiinca in a separate subgenus, 

 Raptiformica, and its slave in another sugenus, Servifonnica, but in my 

 opinion without sufficient justification. 



