BIONOMICS AND DEVELOPMENT OF LYGOCERUS sp. 103 
it is reared; and when it is full-fed, it limes the empty skin 
with silk, and pupates within it. At this time, it is itself hable 
to parasitisation by the Proctotrypids (fig. 1). 
Ly gocerus does not confine itself to Aphididae. Twice 
I have observed its larvae upon newly-transformed and dead 
pupae of its own species. ‘The aphidivorous Braconidae are 
known to be parasitised by certain Chalcidae and Cynipidae, 
some of which were reared from material collected in the 
field in the course of this work. Lygocerus cameroni 
Text-Fic. 1. 
Skin of Macrosiphum urticae cut open to show the full-grown 
larva of its parasite, Aphidius ervi, which has in turn been 
attacked by Lygocerus cameroni. Anegg, and third stage 
larva of the hyperparasite are represented. 
occurred occasionally upon the adult larvae of a Chalcid, prob- 
ably Asaphes vulgaris, and also upon a second species, 
not yet determined, which is possibly a Cynipid (Allotria 
sp.). Apart from the two cases mentioned above, where the 
larva had been hyperparasitised by its own species, Ly go- 
cerus was never found to be attacked by another hymen- 
opteron. 
One remarkable instance of -hyperparasitisation came under 
notice. An aphis (Macrosiphum urticae) had been 
parasitised by Aphidius ervi. The latter had been 
hyperparasitised by an undetermined species of Chaleid. 
This form, after metamorphosis, had been devoured except for 
the frass, the head, and part of the thorax, by a second hyper- 
-parasite, whose life-history is not yet worked out. This larva 
was full-grown when the cocoon was opened, but it had itself 
