Charles Paul Alexander 



Certain European species of Trichocera, such as T. macidipennis (Fabr.) 

 and T. regelationis (Linn.), have been recorded from the Northern States 

 and Canada; these records may be correct, since, as stated above, it is 

 very probable that many species of the genus are Holarctic in their dis- 

 tribution. If such is the case, the names used in the preceding key are 

 very probably synonyms of the European species. 



subfamily Rhyphinat. 

 The subfamily Rhyphinae includes but three genera. The two which 

 are represented by North American species are Rhyphus, with about a score 

 of principally Holarctic species, and Olbiogaster, a tropical group of five 

 species. Within the limits of this paper three species occur, two of 

 which — Rhyphus fenestralis and R. pundatus — are very widespread 

 over the North Temperate Zone. 



Genus Rhyphus Latreille 



1805 Rhyphus Latr. Hist. Nat. Crust, et Ins., vol. 14, p. 291. 



The adult flies of the genus Rhyphus are often found resting on the 

 trunks of trees or on near-by vegetation. The immature stages are 

 spent in decaying vegetable matter, manure, sewage, and similar situations. 

 The venation of a typical Rhyphus is shown in figure 132, a. 



Baerg (1918) has recently published a key for the separation of the 

 adult flies of the three eastern-North-American species of the genus. 

 This key is here modified to conform with the other keys in this paper: 



1. Basal deflection of M-i as long as, or longer than, m (that is, veins Mi, Mi, and Ms about 



equidistant from one another at cell 1st Mi) 2 



Basal deflection of Mi much shorter than m; eyes of male holoptic: no yellowish spot 

 near midlength of costal margin of wing R. pundatus (Fabr.) 



2. Wing with a distinct yellowish spot near midlength of costal margin; subapical hyaline 



spots sharply defined; eyes of male holoptic; median prescutal stripe split by a narrow 



gray line, more distinct in the female R. alternatus Saj' 



Wing with the yellow and hyaline spots less distinct and more diffuse; eyes of both sexes 

 dichoptic; median prescutal stripe only indistinctly divided, if at all. 



R. fenestralis (Scop.) 



subfamily Mycetobiinae 



The subfamily Mycetobiinae, so far as known, includes only the genus 

 Mycetobia, discussed below, and the genus Mesochria of the Seychelles 

 Islands. Other genera have been associated with Mycetobia in the 

 Mycetophilidae, but so far as is known their larvae are quite normal for 



