Dec, 1922. J JOHANNSEN : StRATIOMYIID LaRV.E. 149 



Stratiomyiinae. 



The larvae of several species of each of the genera Stratiomyta 

 and Odontomyia have been described. Some of the European species 

 have long been known. Lundbeck gives a key to several European 

 species, while Hart (1895) and Malloch (1917) have dealt with the 

 biology of several native forms. Of the species of these two genera 

 mentioned in the foregoing keys I have not seen O. vcrtebrata, but 

 have inserted it on the basis of Hart's description. It is quite 

 probable that better diagnostic specific characters may be found than 

 those which I have used. The poor condition and limited number 

 of specimens of some of the species prevented my making use of 

 minor characters which might prove important. The number of 

 hooks on the venter may, indeed, not even be of specific value. The 

 adult of the species which I have called Sp. B in the key very 

 closely resembles the female of O. virgo. My reared specimen of 

 O. pilhnanus is a male; it differs from a typical specimen in having 

 longer thoracic pile and a broader abdominal stripe. 



All the specimens of both genera were collected in ponds or on 

 their margins where the insects go to pupate. When about to 

 pupate, or after pupation, they withstand drying out to a remarkable 

 degree. Their food consists of decaying vegetable matter (or pos- 

 sibly the fungi growing in this), of algae and other small micro- 

 organisms. 



The immature stages of Nothomyia viridis Hine are not known. 



Sarginae. 



The genus Gcosargus is represented by four or five species in the 

 Eastern States. A series of experiments by Dr. J. G. Needham, 

 conducted for the purpose of producing an economical fish food, 

 involved the cutting up of a quantity of the stems of succulent 

 plants and other vegetable matter This material became infested 

 with the larvae of a number of insects among which was Gcosargus 

 dccorus, adults emerging in August. I have also found this species, 

 as well as G. cnprarius, in cow dung. The latter species was also 

 bred by Prof. Britton (1915) of Connecticut from larvae found on 

 the earth, near strawberry crowns. In Europe it was bred by West- 

 wood from garden mold, by Beling from decomposing heaps of 



