64 
several pupe of the parasite Ripiphorus paradoxus, and numbers of the perfect insect, 
both male and female, but could not detect the presence of a larva. 
“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 1 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 fora 
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 the head to the anal 
extremity, cutting each segment across. The skin, during life, throughout the whole 
course of this furrow, is perfectly 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 particles of curd. These appearances vanish 
after death, when the body becomes dense, and has an appearance of solidity about it 
which it had not before. Several pupe of the parasite were found in the nest, as well 
as examples of the perfect insect. It also contained a number of cocoons spun 
by the larve of Anomalon vesparum, with the larve still unchanged inside the 
cocoons. 
“ Between the above date and the 3rd of September I took out thirteen more nests 
of V. vulgaris, which contained examples of Ripiphorus either in the larva, pupa or 
perfect state. In one which had been destroyed by means of gas tar a few days before 
I took it out, I was fortunate in discovering a small larva of Ripiphorus firmly attached 
to its victim. Both were dead and had become partially dried, so that when im- 
mersed in spirits they did not separate, but remained attached just as they were 
before death. These are interesting, because in them may be seen the exact way in 
which the parasitic larva fastens on ils prey. In another, which I took out on the 
2nd of September, I found, on opening some closed-up cells appropriated to queens, 
one larva and une pupa, which differed in nothing that I could discover from those of 
Ripiphorus found in the cells of workers, except that they were something like double 
the size; in fact, about as much larger as the larve and pupe of queen wasps are 
larger than those of workers (ante, pp. 49, 58). 
“Until the present summer I had not met with a specimen of Ripiphorus since 
the year 1859, although I had made diligent search for it every succeeding summer. 
What had become of it all that time, and how it was that all at once it made its 
appearance in such numbers, are questions more easily asked than answered. Where 
it occurs it appears to be very local, for I have never met with it except in one 
particular part of Cokethorpe Park, within a space of ground about four furlongs in 
length by two in width. I have searched yearly for it in nests obtained from other 
parts of the park and the surrounding neighbourhood, but always in vain. 
