flPltNCULIDAC. 
613 
interesting economically, as they are parasitic upon Rhynchota (especially 
Jassidce and Fulgoridce) in whose bodies the small thick oval larvae live 
until full grown ; they may then force their way 
out between the thorax and abdomen and fall 
to the ground, where they hide themselves 
and turn to smooth black puparia (fig. 406). 
The flies themselves are generally caught 
by sweeping flowers and undergrowth, and 
though owing to their retiring habits they are 
not often seen they are really not uncommon 
in the plains, while in the hills they can be 
found in fair abundance when looked for. 
Though they fly with none of that flash¬ 
ing rapidity characteristic of Syrphids and 
Bombyliids they are certainly not inferior to these two families in their 
extraordinarily accurate control over their flight, which is probably 
unsurpassed by any insect. When seek¬ 
ing their prey among grass and other 
herbage, their irregular and wandering 
flight may easily cause them to be mis¬ 
taken for small Hymenopterous para¬ 
sites, but their faculty of hovering in a 
confined space is remarkable. We have 
sometimes imprisoned them in glass 
Fig. 
405— Ante nx a 
P lPUNCULUS. 
(After Perkins ) 
OF 
Fig 
406— PlPUNCULID PUPARIUM 
(x abt. 12) & Diagram of Hopper 
TO SHOW POSITION OF PUPARIUM 
IN THE BODY. 
(After Perkins.) 
tubes (J-J in. wide by 3 in. long) for the 
pleasure of witnessing an exhibition of 
this power : they will repeatedly hover 
from end to end of this small space 
without apparently ever touching the 
glass, or will remain with the body 
quite motionless, suspended in the 
middle of the tube. According to Jenkinson (Ent. Mo. Mag., 1903 ; 
p. 222) the female poises herself thus before she darts at and seizes the 
victim in whose body she will lay her eggs. 
In view of their specialized parasitic mode of life it is interesting 
to compare these flies with the Asilidce and Empidce , which also hunt 
their prey by sight. In all three families we find big eyes set in a very 
