LIVE-HISTORY OF LIOTHULA OMNIVORA., 541 
smaller larve of the males sometimes contain but a single parasite. 
These pup are dark chestnut-brown in colour, with distinct articula- 
tions; their length is nearly three lines, and they are of the ordinary 
coarctate form. The perfect insect is a brilliant green fly, the. 
abdomen being almost blue; the scutellum is bordered with fulvous, 
and the legs are black; the whole insect is also covered with 
numerous black bristles; its length is about three lines. A descrip- 
tion of this fly may be found in the “Catalogue of New Zealand 
Diptera,” where it is described for the first time under the name of 
Hurigaster marginatus. 
Among a large number of the exuviz of this species I found one 
which had not emerged. Knowing that all the individuals of a single 
brood of dipterous insects always appear within a few hours of one 
another, I was anxious to ascertain what had occasioned the protracted 
emergence of this specimen, and in order to do so I enclosed it in a 
small tightly-fitting box. On examination about ten days afterwards 
I discovered eighteen small Chalcids had escaped through a small 
round hole near its anterior end; four of these are considerably 
smaller than the rest, but do not differ in any other respects, and are 
no doubt males. 
Owing to my very imperfect knowledge of the New Zealand 
Hymenoptera, I think it would be useless for me to attempt to 
describe an obscure species of this kind at present. I therefore 
enclose specimens, should they at any time be required, and leave the 
description to someone who is better able to perform the task than 
myself.* 
I have not yet been able to discover how the Chalcid introduces 
its eggs into the Dipteron; nor is it likely to be discovered, except by 
the most minute observation. It is certain that a full-grown maggot 
would not suffice to nourish eighteen Chalcid larve, which collectively 
equal it in bulk after it had ceased feeding; hence it is evident that 
the eggs are not deposited in the dipterous larva when it has left the 
caterpillar. If, on the contrary, they are introduced into the maggot 
while it is within the Liothula larva, the hyperparasite must either 
promiscuously deposit in every caterpillar it comes across all the 
eggs, except those which reach a dipterous maggot never hatching, 
or it must by some extraordinary means be able to single out those 
caterpillars infested by Diptera and oviposit in them, occasionally 
perhaps missing the maggots lying within, as Mr. Bignell conjectures 
in the case of Abraxas grosswlariata (Kntom. xiii. 245). Both of these 
suppositions are, to my mind, contradicted by the fact that out of six 
dipterous pupx taken from a single caterpillar only one was infested 
with Chalcids, and that contained eighteen. Now it would be a 
remarkable circumstance indeed for a female Chalcid to oviposit in a 
caterpillar eighteen times, striking an enclosed maggot every time, 
and not any of the five others once. I prefer to consider, until actual 
observation proves it fallacious, that both Hurigaster and the Chalcid 
enters the Liothula’s case together by the posterior aperture, the latter 
possibly clinging to the former. The Dipteron then lays a number of 
eggs on the skin of the caterpillar, as is the case with all parasites of 
* Two specimens of this Péeromalus, and a third partially destroyed, are deposited 
in the British Museum.—E. A. F, 
