97 
NOTE ON THE SUPPOSED LARVA OF PIMPLA OCU- 
LATORIA, F., FIGURED IN MORLEY’S ‘ BRITISH 
ICHNEUMONS,’ VOL. III., 1908, AND ITS LOCATION 
AMONG THE DIPTERA. 
By J. H. Conum, F.E.S. 
Mr. Craupr Morury has described and figured on p. 114 
of his latest volume on British Ichneumons what he supposed 
might be the larva of Pimpla oculatoria, F., found in an egg-bag 
of Epeira diademata, taken from under the coping of a garden 
wall in Ipswich; this larva cast its skin soon after he found it, 
but ultimately died. 
To Mr. Morley this was an “‘ichneumonidous larva of most 
unusual form and colour;”’ still, the known fact of the asso- 
ciation of P. oculatoria with spiders, and of its having been bred. 
from the egg-bag of this particular spider, naturally led him to 
believe that the connection between the larva he found and the 
ichneumon, though ‘ unsatisfactory,” was “‘ extremely probably 
correct.” 
My attention was attracted to his figure by its great simi- 
larity to the larve of some Diptera, while the fact that Mr. 
Morley had found in another egg-bag of the same spider given 
to him by the Rey. O. Pickard-Cambridge one similar larva- 
skin with ‘the very distinctive rostrum of the . . . described 
larva,’ and in the same egg-bag were Four cocoons of the 
Pimpla, favoured the conclusion that this must be a Dipterous 
larva with the Pimpla parasitic upon it. 
Mr. Morley generously allowed Dr. Sharp to examine the 
larval skin, and he writes: ‘‘It is no doubt that of a Dipteron 
of the family Stratiomyide. From its appearance it may have 
been parasitised; it has, at any rate, not been naturally cast off.” 
It would therefore appear that there must be a species of 
Stratiomyide, living in the larval state upon the eggs of Hpeira 
diademata, though the present knowledge of the larval habits 
of the family in no way supports the possibility of such an 
occurrence. The only genus of Diptera in the neighbourhood 
of the Stratiomyide, said to have been bred from the cocoons of 
spiders, is Acrocera (Cyrtide), but the presence of Acrocera in 
the middle of Ipswich would be somewhat remarkable. 
It remains for someone to clear up this interesting question 
by rearing one of these larva, which unfortunately Mr. Morley 
failed to do. 
[That the attack upon the spiders’ egg should be in. the 
form of hyperparasitism has never before been suggested, and 
certainly did not occur to me when writing my article upon 
the subject (Ichn. Brit. iii. 113-115), which is certainly worthy 
of very close attention (cf. Grav. Ichn. Hurop. i. 154; Westw. 
Mod. Class. ii. 148; Laboulbéne, Ann. Soc. France, 1858, p. 800, 
ENTOM.—APRIL, 1909. I 
