888 CHARLES PauL ALEXANDER 
Certain European species of Trichocera, such as T. maculipennis (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 Bey are 
very probably synonyms of the European species. 
SUBFAMILY Rhyphinae 
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. punctatus — 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 M2 as long as, or longer than, m (that is, veins Mi, M2, and M; about 
equidistant from one another,at cell /st Ms)s- 22. 2.) a eee 
Basal deflection of M2 much shorter than m; eyes of male holoptic; no yellowish sa 
near midlength of costal margin of wing........................ R. punctatus (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 
pray, line, more’distinctuincthe female == 4-6. +24. oe ace eee R. alternatus Say 
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 
