234 ON AN ICHNEUMONID LARVA 
an oblong oviform figure, somewhat depressed on the 
underside ; it is whitish, with a faint tinge of yellow 
extending along the medial line of the upper part, 
which seems to be occasioned by the contents of the 
viscera. At this period of its existence the external 
covering presents a smooth, uniform surface; but 
when its has completed its moultings and attained to 
its full size, the head becomes visible, the body ex- 
hibits thirteen distinct segments, a series of dorsal 
prolegs is developed on the segments comprised 
between the third and tenth, both inclusive, and its 
prevailing hue is dark brown streaked and spotted 
with white, particularly on the sides. The dorsal 
prolegs are short, and, with the exception of that on 
the tenth segment, are more or less bifid at the 
summit; on their extremities numerous fine curved 
processes or claws are disposed, with which the larva, 
when about to fabricate its cocoon, attaches itself to 
the lines spun by its victim. Only two instances are 
noticed by Messrs. Kirby and Spence in their ‘ Intro- 
duction to Entomology,’ sixth edition, vol. 1. pp. 227, 
228, of the larvee of insects having prolegs situated on 
their backs. 
In April 1838, I captured a young female Lpeira 
antriada with one of these parasites upon it, and 
placing it in a phial of transparent glass, I supplied 
it with flies. Towards the end of May, having gone 
through its final moult and increased considerably in 
size, this larva became very restless, and on the 29th 
