358 
Life-history of Melittobia acasta 
Malyshev (1911) had observed the puncturing in connection with ovi- 
position and he regarded its function as twofold; first to paralyse the host 
and secondly to preserve it, but here, I think, he went too far. He only 
mentions one case, in which he saw a larva of Odynerus antilope receive three 
punctures in the beginning of September and he remarks that it remained 
soft and fresh, without showing any other sign of life, until the following May, 
when it dried up. Had this larva not been punctured at all it would have 
remained soft and fresh until the following May when it would have pupated. 
There seems to me to be no need to imagine any preservative effect, apart 
from which there is good reason for believing that there is none, since in every 
case where eggs were laid upon eggs or immature larvae of a host, these host 
eggs and larvae quickly collapsed and showed all the usual signs of decay. 
It is sufficient then to regard this preparation of the host by the injection 
of some paralysing fluid as similar to that seen in those solitary wasps which 
store up living food for their progeny. 
So far as my observations go, this “stinging” by Melittobia always takes 
place at least once, and sometimes frequently, before any eggs are laid, 
although Malyshev asserts that oviposition may be commenced before any 
“stinging” takes place, though this is less usual. 
(c) Oviposition. 
Melittobia is in all cases ectoparasitic and the statement of Malyshev that, 
under certain circumstances, it is an endoparasite is misleading. Thus he 
speaks of it as becoming endoparasitic when it oviposits through the cocoon 
of an hymenopterous host or the puparium of a fly. 
I have opened numbers of fly puparia after having observed Melittobias 
puncturing them but in no case did I find any eggs except on the enclosed 
pupa. 
When a female is about to lay her eggs she moves over the host, tapping 
with her antennae until she finds a suitable spot. Such a spot is usually, though 
not always, upon the upper side of the host larva or pupa as it lies in the cell, 
whether it be dorsum or venter uppermost and, if there is any choice of 
position, of which I am doubtful, the head end is more favoured than the apex 
of the abdomen. 
Having selected the spot the female brings the apex of her abdomen into 
contact with the surface of the host and, having fixed the apex of the ovipositor 
in the chi tin, the apex of the abdomen withdraws to its normal position. So 
far the action has been that of a feeding or a “stinging” female but, for ovi¬ 
position, the ovipositor is not driven into the host, merely remaining fixed 
by its apex. 
The abdomen can now be seen slowly expanding and contracting until, after 
a few such movements, a slight bulge appears at the base of the ovipositor 
on its anterior side and this bulge rapidly passes downwards and the egg 
suddenly shoots out near the apex. It is a most extraordinary sight and looks 
