Wasps 



Ashmead has found an American Scolia preying upon the larva 

 of still a third beetle. 



The so-called solitary ants, of the family Mutillidae, are very 

 common in portions of the United States. Most of them are 

 clothed with hair, which is frequently bright-colored in some 

 of them being bright red and on account of the velvety appear- 

 ance which this hair gives them they are sometimes called velvet 

 ants. In this group there is admirable opportunity for the study 

 of life histories, since comparatively little is known about the 

 way these insects live. They are no doubt parasitic in the nests 

 of bees, and in Europe one species is known to live in the larval 

 state feeding upon the larvae of a bumblebee. Schwarz, in this 

 country, reared one of them from the cells of a burrowing bee, 

 Riley another from the cells of another burrowing bee, and 

 Davidson from an anthophorid bee. 



Many strikingly beautiful insects belong to the family Chrys- 

 ididse. They are called cuckoo flies by the English writers, and 

 goldiuespen, or gold wasps, by the Germans. The colors are 

 usually brilliant metallic green or blue, and the abdomen is fre- 

 quently tipped with red. The larger species reach the length of 

 half an inch or more, but the commoner forms in the United 

 States are small insects, seldom reaching three-eighths of an inch 

 in length. They are rather stout-bodied insects, and are readily 

 distinguished from the slender wasps of the preceding groups. 



Careful studies of the economy of any of our North American 

 species are greatly needed. Walsh reared Chrysis ccerulans from 

 the cells of one of the potter wasps (Eumenes fraterna), and Ash- 

 mead has seen one of them entering the burrows of a Trypoxylon, 

 while he reared two species from the cells of a mud-dauber and 

 one from the cells of an Odynerus. They are, therefore, either 

 parasites or guests in the nests of wild bees and wasps, and are 

 probably parasites rather than inquilines. In Europe some species 

 of the genus Cleptes are true parasites on saw-fly larvae. There 

 is a curious confusion sometimes in an Odynerus cell, for a Try- 

 poxylon will enter one carrying its own store of food with it, and 

 closing the entrance against the return of the female Odynerus; 

 then comes along a Chrysis and lays an egg, from which hatches 

 a larva which devours the stores of the Trypoxylon. The larva 

 of the cuckoo fly is said to transform without cocoon to a pupa, 

 and in this state to pass the winter. 



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