HYMENOPTERA 937 



occidentalis, which measures from 1 6 to 30 mm. or more in length, is 

 known in the South as the "cow-killer ant" because of the popular 

 superstition that its sting is very dangerous to live stock. 



Andre ('03) states that the mutillids of which the habits have 

 been observed are parasites of nest-buildins? H^inenoptera in the cells 

 of which they deposit their eggs. The larvae attack those of the 

 owners of the nest without touching the provisions which the cell 

 may contain. 



In this country a species has been reared from the cells of the 

 solitary bee, Noniia pattern, and one from the nests of the mud- 

 dauber, Chalybion ccErnlemn. In Europe several species are parasitic 

 in the nests of bumblebees; and in Africa several species have been 

 found to be parasitic on the tsetse fly. 



The Mutillid£e of North America have been monographed by Fox 

 ('99) and those of the Eastern United States by Bradley ('16). 



Family SCOLIID^ 

 The Scoliids 



The scoliids are quite closely related to the preceding family but 

 differ in their general appearance, resembling wasps rather than ants. 

 They are parasitic on white grubs, the larvaj of Scarabasidae. In 

 their habits they do not exhibit as much intelligence as do most digger 

 wasps; for they do not build nests and transport prey to them for 

 their carnivorous larvae. Instead of this they dig in the ground 

 where the white grubs are, and finding one they sting it in order to 

 paralyze it, work out a crude cell about it, and attach an egg to a 

 ventral abdominal segment of the grub. The larva of the scoliid con- 

 sumes the grub and then spins a cocoon and completes its development 

 in this place. 



The members of this family are very striking in appearance, being 

 of large size and with the abdomen marked with conspicuous spots. 

 Two genera are represented in our fauna, Scolia and Campsomeris 

 {Elis) . In Scolia the transverse part of vein M2 of the fore wings is 

 wanting, in Campsomeris it is present. 



Family FORMICID^ 



The Ants 



The great number of ants and their wide distribution render them 

 the most familiar of all insects except perhaps the house-fly. As has 

 been said by Professor Wheeler, an indefatigable investigator of these 

 insects, "Ants are to be found everywhere, from the arctic regions to 

 the tropics, from timberline on the loftiest mountains to the shifting 

 sands of dunes and seashores, and from the dampest forests to the 

 driest deserts. Not only do they outnumber in individuals all other 

 terrestrial animals, but their colonies even in verv circumscribed 



