622 
DIPTERA. 
The larvae are typically leaf-miners or live in stems, but have also 
been found in the galls of other insects, while some of them probably 
live in fungi, and one Indian species of the genus Leucopis is known to 
be predaceous, feeding on scale insects. They are, like most of the larvae 
of Acalyptrates, small white maggots with horny mouth-hooklets but 
no definite head, the body rather thick at the hind end and tapering to 
a point in front. Some very common and beautiful flies of this family 
may often be seen hovering like little silver fairies in and out of the 
shadow of tree-trunks. They have the abdomen greyish white and 
shining, like metallic silver (PL LXVII, fig. 1), and have been bred 
from larvae found in stems of Gurur. 
There are three Agromyzids which are known to be important to 
the agriculturist ; they are the Tur-pod fly, the Pea-stem fly, and the 
Cruciferous Leaf-miner. The 
Pea-stem and Tur-pod flies are 
figured on PL LXVII, figs. 2 & 3. 
The latter is a very black little flv 
whose eggs are laid in the setting 
flowers of Tur ( Cajanv.s Indicus). 
The larvae on hatching eat their 
way into the green seeds, forming 
a ring-like track round the seed, 
and after about a week they 
pupate within the pod, generally 
outside the seeds ; the fly emerges 
in a few days, the whole life- 
history occupying a fortnight or 
less. Affected pods usually have 
a somewhat twisted and distorted 
appearance (fig. 409). A slender 
blue-green hymenopterous para¬ 
site attacks the fly, but to what 
extent it is effective as a check 
is not yet known. The Pea-stem 
fly is very similar in general 
appearance to the Tur-pod fly 
but is dark metallic green in colour. The larvae, which are of the 
usual type, attack the stems of young pea plants at a point level with 
Fig. 410— Pods of cajanus indicus af¬ 
fected by the Tur-pod Agromyza. 
A PUPARIUM IS LYING AT THE TOP OF 
THE RIGHT-HAND POD. 
