2586 Insects. 



humble bees. There is also a larva in humble bees' nests, which is extremely like 

 that of Volucella pellucens, but whether it is this species I am unable to say, as 

 I failed to breed it some years ago, when I had captured several, and was trying to do 

 so. These larvae, at least, in their early stages, are found crawling about the loose stones 

 and earth immediately below the nests of wasps. When the wasps (Vespa vulgaris 

 and V. rufa) excavate the cavity in which their nests are built, they are unable to re- 

 move large stones, which continue to subside as the excavation advances, and, ulti- 

 mately, form a sort of rude pavement below. I have placed an example or two of 

 this in the Kew Museum. These stones are kept moistened by matter dropping from 

 the nest, and on this and dead wasps, the maggots seem to revel. But later in the 

 season I find them, especially those of the Volucella, travelling about among the comb 

 itself. I have not witnessed the fact in the case of wasps, but in that of the humble 

 bees, I have repeatedly seen these parasitic larva; attack the pupa; of the bees, and a 

 curious process it was to witness. They would work at the cocoon in which the pupa 

 was enclosed, extending and briskly agitating their mouth and moistening the surface, 

 till, in a short time, they had worked a hole through it : they then pierced the 

 helpless pupa of the bee, entered its body, and devoured the whole of its interior, leaving 

 the case as clean picked as the shell of a lobster by a hungry supper-eater: I have 

 preserved a couple of these empty cases, which I saw cleaned out about twelve years 

 ago. When satisfied with their meal, they come out, and then appear gorged and 

 half torpid, and are covered with a moist disagreeable exudation, reminding one of the 

 descriptions given by Arctic travellers of a gluttonous Esquimaux surfeited with blub- 

 ber. I have several times seen the larva of Exorista devia come out of the pupa; of 

 humble bees, and turn to pupa; themselves, which I have bred into flies. As the larvae 

 of these humble-bee parasites are found crawling about at the bottom of their nests, 

 just as those which we find under wasps' nests, I am inclined to think that these latter 

 also finish up their last meal much after the same fashion as the former: I have never 

 witnessed the fact (as I said before) because it is not so easy to follow up this sort of 

 observation in a wasp's nest, as in that of a humble bee, without more care than I have 

 thought fit to bestow upon the investigation. Entomologists will be satisfied that I 

 have given the right names to these Diptera, when I mention that I have Mr. Curtis's 

 authority for them. It has been more through his expressed wish that I should state 

 what I had witnessed of the habits of these larvae than from any belief that I had any 

 thing very novel to record, that I am induced to send you this account. — /. S. 

 Henslow ; Hitcham, Hadleigh, Suffolk, September 11, 1849. 



On the Economy of Alherix Ibis. — In your notice of the Proceedings of the Ento- 

 mological Society on the 2nd of July last, (Zool.2531), Mr. Westwood is stated to have 

 shown some flies and their eggs, part of a cluster found about twelve miles from 

 Derby, and sent to him by Mr. Spencer, of that town, who had remarked, that each fly 

 seemed to remain as a protector of the eggs it had deposited. They were identified as 

 Atherix Ibis. As some further account of the discovery of this nest may be interesting 

 to the readers of the ' Zoologist,' and may tend to throw some light on the natural 

 history of the insect, I have obtained, from the same very intelligent gentleman, the 

 following additional particulars. This cluster of insects was found on the 1 1th or 12th 

 of June last, upon a bough of hawthorn, hanging about a foot above a brook of five feet 

 wide, called Garendon Brook, nearly one mile from the village of Hatbern, in 

 Leicestershire, by Mr. William Frederic Phillipps, son of the rector of Hathern. It 

 appeared like a swarm of bees on a small scale, being about the size of the hand of a 



