399 



HABITS OF IMAGINES 



Imagines of a few common species may be collected from win- 

 dows. They are not predaceous, feeding as far as we have observed 

 upon nectar or moisture. 



Scenopinus fenestrates Linne 



Musca fenestralis Linne, Fauna Suecica. (1761) 



Larva. — Length, 18-20 mm. White. 



Very slender, tapering towards both extremities. Head conical 

 (PI. LVII, Fig. 2). Thoracic hairs as long as or longer than the seg- 

 ments upon which they are situated; spiracles distinct (PL LVI, Fig. 

 11). Anterior division of abdominal segments 1 to 6 about one half 

 longer than posterior ; posterior spiracle about one third from anterior 

 margin of antepenultimate segment; apical segment divided (PL LVI, 

 Fig. 8), the surface hairs long. 



The foregoing description was made from specimens obtained at 

 Urbana, 111., November 3, 1892, under a carpet, where they were 

 feeding upon larvae of Tinea tapctzclla (C. A. Hart). 



The species was not reared and no pupae are available, the charac- 

 ters used in the key and elsewhere in this paper being obtained from 

 published descriptions. 



The species occurs commonly both in Europe and North America. 



Tribe Orthogenta 



This tribe of the Brachycera contains one superfamily, 

 Empididoidea, and two families, Empididae and Dolichopodidae, both 

 of which contain a very large number of species. 



Superfamily Empididoidea 



CHARACTERS OF TRIBE AND SUPERFAMILY 



Larva. — The larvae of both families as far as known, differ from 

 others in Brachycera in having the labial plates and the longitudinal 

 rods meeting at right angles, so that in profile they appear bent. The 

 maxillary palpi are usually small and the antennae distinct. In all 

 species that I have examined there are 4 slender elongate posterior 

 cephalic rods, the larvae are amphipneustic, and the locomotor organs 

 are more or less developed, consisting of paired pseudopods, of fusi- 

 form ventral areas armed with spines, or of transverse series of short 

 spinules. The posterior spiracles are upon the apical abdominal seg- 



