638 
DIPTERA, 
HETERONEURIDiE. 
Small rather slender flies, with vibrissce. R l and anal veins short; sub¬ 
costa not very distinct, cross-veins quite close together. 
A small and unimportant family. No Indian species have been 
bred, and the flies are uncommon. In Europe the larvae have been 
found in decaying wood and the flies occur in rather damp shady 
places. One species has been seen at Pusa. 
CORDYLURIM. 
Sub-costa distinct, costa not bristly at its end. ls£ posterior cell not nar¬ 
rowed. Two basals and anal present. Head rounded, the eyes round 
and bare, the front broad in both sexes. Abdomen with at least five 
visible segments. Squamce small. 
This family, with the Anthomyiidce, is transitional between the 
Acalyptrates and the Calyptrates. To the Anthomyiidce it is very closely 
related, and with some species it is most difficult to decide in which 
family they should be placed. The chief difference is that the Antho- 
myiids have the eyes usually closer together in the male than in the 
female, while both sexes of the Cordylurids have the eyes wide apart, 
and in them the structure of the genital organs affords the best means 
of distinguishing the sexes, the males usually having the abdomen 
blunter and more rounded than the females. Contrary to what is 
usually the case, the males of some Cordylurids (e.g., Scatophaga) are 
very considerably larger than the females. Many of the flies breed in 
dung. These are chiefly the Scatophagince. The other genera are 
usually found in wet places near ponds or tanks, and several of their 
larvae live in the stems of water-plants, while one genus Clidogastra has 
occurred as a parasite in a Noctuid caterpillar (Williston). The larvae 
are variable in structure, but those of Cordylurince are amphipneustic 
with both pairs of stigmata conspicuous. Little seems to be known of 
the life-histories and they have not yet been studied in India, with the 
exception of the Cordylurid figured on PL LXYI, the “ Rice-stem fly.” 
The larva and the characteristically truncated pupa are sufficiently 
described by the picture. The fly differs from most allied Cordylurince 
in having no conspicuously large bristles on the mesonotum (dorso- 
central bristles). The larvae live in the stems of young rice and pupate 
there ; mature stems are rarely or never attacked : the wilted-looking 
