1924] Phylogeny and Interrelationships N ematocerous Diptera 239 
dipteran stem represented by such forms as Austropsyche, etc., 
described by Tillyard, 1919. 
The Bruchomyidse are very like the ancestors of the Psy- 
chodidae, which branched off from the Bruchomyid stem to 
follow their own isolated path of development. On account of 
the isolated character of the Psychodidse, which differ from 
both the Tipuloid Nematocera (Pronematocera) and nori- 
Tipuloid Nematocera (Eunematocera) the Psychodidae and 
their ancestral types, the Bruchomyidae, might possibly be 
grouped together as Paranematocera, composed of the super- 
family Psychodoidea but this point is of no particular importance 
in the present discussion. 
The Tanyderidae are among the most primitive of the 
Tipuloid Nematocera, and have departed but little from the 
ancestral Dipteran stock, but they have developed modifica- 
tions of their own, and it would be impossible to derive the 
rest of the Tipuloid Nematocera from this family alone, although 
it is possible that the Tipuloid family Ptychopteridse branched 
off from the ancestral Tanyderid stem, as shown in Fig. 1 . 
The Tipuloid subfamily Trichocerinse of Alexander, is here 
raised to family rank, because the Trichoceridse differ markedly 
from the Anisopodidse (Rhyphidse) in which family they have usu- 
ally been placed. On the other hand, the Trichoceridse are very 
like the ancestors of the Anisopodidse, and apparently had a 
common origin with the Anisopodidse, from which common 
origin they have departed less than the Anisopodidse have. The 
ancestors of the Trichoceridse arose from the common stem 
giving rise to the Bruchomyidse and Tanyderidse, and it would 
be impossible to derive the Trichocerids from any known Bru- 
chomyid or Tanyderid. The rest of the Tipuloid Nematocera 
are of no particular interest in the study of the lines of develop- 
ment of the non-Tipuloid Nematocera, and need not be further 
considered here. 
The Anisopodidse (Ryphidse) furnish the ^‘key’^ group in 
tracing the phylogeny of the non-Tipuloid Nematocera, and it 
is a question as to whether the Anisopodidse are still to be con- 
sidered as true Tipuloid Nematocera, or whether they have 
progressed far enough toward the non-Tipuloid Nematocera 
