152 INSECTS AT HOME. 



for entomologists were undecided as to its food, though they 

 conjectured that, like many, though not all, parasitic Beetles, 

 it fed upon wasps or their larvae. This question was, however, 

 completely set at rest by the late Mr. S. Stone, in a series of 

 experiments on insects that were parasitic on the bees and 

 wasps. Some of Mr, Stone's extraordinary achievements with 

 these insects will be mentioned in connection witli the Hymeno- 

 ptera. In the ' Proceedings of the Entomological Society,' Jan. 

 2, 1865, Mr. Stone made a series of valuable communications 

 on this subject, which ought to be given in his own words. 

 After mentioning that he had previously found the pupae and 

 male and female Beetles, but could not detect a single larva, 

 he proceeds as follows : — 



'On the 19th I was more fortunate, for, on taking out a nest 

 of V. vulgaris and proceeding to open the closed-up cells, I 

 found a larva of the parasite firmly attached to the full-grown 

 larva of the wasp ; the mouth of the former buried in the body 

 of the latter just below the head; its neck bent over that of 

 its victim, whose body appeared to be tightly compressed by 

 that of its destroyer, showing the latter to be possessed of a 

 considerable amount of muscular power. It was of minute size 

 when discovered, and appeared to have only very recently 

 fastened upon its victim ; but so voracious was its appetite, 

 and so rapid its growth, that in the course of the following 

 forty-eight hours it attained its full size, having consumed 

 every particle of its prey with the exception of the skin and 

 mandibles, which, from observations I have since been enabled 

 to make, these creatures retain in their grasp even after they 

 have passed into the pupa state. They scarcely appear to cease 

 eating, except now and then for a minute or so, from the time 

 they first begin to feed till they have become full-grown. The 

 larva is a singular-looking one. The head is bent forward 

 under the body. Between the segments it is more deeply 

 furrowed than any larva with which I am acquainted. A 

 longitudinal furrow extends down the back from tlie head to 

 the anal extremity, cutting each segment across. The skin, 

 during life, throughout the whole course of this furrow, is per- 

 fectly transparent, so that the workings of the internal organs 

 may be plainly seen. The body of the larva, while alive, has the 

 appearance of a thin transparent skin filled with minute par- 



