LIFE-HISTORY OF RHIPIPHORUS 697 



is actually needed for its bare existence, at once induces rotundity 

 of body and a loss of power in the limbs, followed by their partial 

 or total atrophy. 



That this process of degeneration may even occur in one and the 

 same stage of larval existence is very well illustrated by what we 

 know of the life-history of the wasp-parasite of Europe, Rhipiphorus 

 paradoxus. Thanks to the very careful and patient observations of 

 Dr. T. A. Chapman, we have a nearly complete life-history of this 

 beetle, the representative of a family in many respects connecting 

 the Meloidae and Stylopidse. 1 Where Rhipiphorus lays her eggs is 

 unknown. Dr. Chapman, however, found a solitary specimen of the 

 young larva in the triungulin stage. He describes it as "a little 

 black hexapod, about J^- inch (.5 mm.) in length, and yi^ inch in 

 breadth, broadest about the fourth segment, and tapering to a point 

 at the tail; a triangular head with a pair of three-jointed antennae 

 nearly as long as the width of the head, with legs very like those of 

 Meloe larvae ; the tibiae ending in two or three claws, which are sup- 

 ported and even obscured by a large transparent pulvillus or sucker 

 of about twice their length ; this was marked by faint striae radiat- 

 ing from the extremity of the tibiae, giving it much the aspect of a 

 lobe of a fly's proboscis. Each abdominal segment had a very short 

 lateral spine pointing backwards ; the last segment terminated by a 

 large double sucker similar to those of the legs ; and the little animal 

 frequently stood up on this, and pawed the air with its feet, as if in 

 search of some fresh object to lay hold of." 



This almost microscopic larva finds a wasp grub and bores into its 

 body, probably entering at a point near the back of the first or second 

 segment behind the head. Dr. Chapman succeeded in finding the 

 larva of the beetle within that of the wasp, before the latter had 

 spun up. '' Assuming that the wasp larva lives six days in its last 

 skin before spinning up, I should guess that the youngest of these 

 had still two or three days' feeding to do. The Khipiphorus larvae 

 were but a little way beneath the skin of the back, about the fourth 

 and fifth segments [counting the head as the first], and indifferently 

 on either side. The smallest of these was J-g- inch in length, and. 

 except its smaller size, was precisely like the larger ones I am about 

 to refer to, having the same head, legs, plates, etc. These were of 

 the same size as those of the larger larvae, the difference in size 

 of the latter being due to the expansion of the intermediate colorless 

 integument." 



1 Some facts towards a life history of Rhipiphorus paradoxus. Annals and 

 Magazine of Natural History for October, 1870. 



