Gr. S. GrRAHAM-SMITH 
371 
Malyshev (1913) made some very interesting observations on the habits 
of M. acasta as a parasite of solitary wasps. He states that the females can 
only fly 1-2 mm. The females frequently wound the wasp larvae with their 
ovipositors and suck the wounds. Such larvae never moult, make a cocoon 
or transform, but are immobilised and finally die, though very slowly. The 
females lay 200-300 eggs, or perhaps more. The males emerge first and fights 
ensue in which some are decapitated or loose their legs or abdomens. He notes 
that virgin females only lay four or five eggs, which give rise to males. Such 
females then wait in the neighbourhood and eventually mate with the males 
which emerge, and within 24 hours lay numerous eggs. The males never leave 
the nests in which they were hatched. He states that M . acasta attacks the 
tachinids which parasitise the wasps. They never lay their eggs on the 
tachinid (P. signatus ) larvae, which are very lively, but wait till they pupate 
and oviposit on the puparia. 
Dibrachys cavus. 
D. cavus was first encountered in small numbers in puparia collected in the 
autumn of 1914. From thirteen of these 37 of the parasites emerged in April 
and May 1916. Fly puparia collected in the autumn of 1915 showed however 
heavy infection with this parasite. Some of these parasites emerged in Sep¬ 
tember 1916, namely 19 $ and 65 $ from 15 puparia. The remainder did not 
commence to emerge till March or April 1917. Then 433 D. cavus emerged 
from 154 puparia, the sexes being nearly equal in numbers. The numbers 
