22 ANDRENIMD. 



The depth of the burrows formed by these bees varies from about 6 

 to 10 or 12 inches. At the bottom of the burrow is a small oval 

 cell in which the industrious female stores up a small mass of pollen 

 mixed with honey ; these little balls of provision for the bee-larva 

 are usually about the size of a garden pea ; from the main tunnel 

 short branch-tunnels are excavated, each terminating in a cell simi- 

 lar to that at the end of the main one. When the requisite quantity 

 of food is stored up, an egg is deposited on the mass, on which the 

 larva, when hatched, commences to feed: having consumed it and 

 being now full-grown, it reposes in a lethargic state until the ap- 

 proach of the following spring, or season w 7 hen it changes to the 

 pupa state, and through that rapidly to the perfect insect. Some 

 species are strictly summer bees, not appearing before the months 

 of June, July, or August ; but the economy of these corresponds 

 with that of the earlier species. 



These bees are subject to the attacks of parasites. The first to be 

 remarked upon are those bees which compose the genus Nomada ; 

 they are more popularly known as wasp-bees, since they bear a con- 

 siderable resemblance to some of the small solitary species of that 

 family. These parasites appear to be upon a perfectly friendly footing 

 with the industrious bees, and are permitted, without let or hin- 

 drance, to enter their burrows. It has been advanced as a proof of 

 the ingenuity and artifice necessary to be employed in effecting the 

 deposit of their eggs in the working-bees' nests, that the parasites 

 should bear a close resemblance to the bees upon which they are 

 parasitic. Some instances may undoubtedly be advanced, as Apa- 

 thus and Bombus, and also in the different species of Volucella which 

 infest the nests of humble-bees ; but amongst the solitary bees no 

 such resemblance is required to aid in any necessary deception. It 

 may be remarked that the two cases are not analogous : this is true, 

 and I am not prepared to say that in the case of the Bombi and their 

 enemies it, may not be necessary ; but as regards solitary bees it 

 certainly is not — colonies of Andrenidse and their parasites mingle 

 together in perfect harmony, issuing from and entering into the 

 burrows indiscriminately. I have on several occasions watched with 

 much enjoyment a large colony of Eucera longicornis, the males oc- 

 casionally darting forwards with great velocity, then turning sharply 

 round, and, as it were, swimming in circles close to the ground, 

 then darting off again and again in an unceasing round of sportive 

 enjoyment; their industrious partners, whose whole existence ap- 

 pears to be bound up in one unceasing round of labour, would occa- 

 sionally return home laden with food for their young progeny. Some- 

 times it would happen that a Nomada had previously entered her 

 nest ; when such proved to be the case, she would issue from it, and, 

 flying off to a short distance, wait patiently until the parasite came 

 forth, when she would reenter and deposit her burden. It will be 

 observed in this instance that between Eucera and Nomada no re- 

 semblance exists in general appearance, one being several times 

 larger than the other and covered with pubescence; of a sombre 

 colour ; whereas the parasite is a gaily-coloured insect, destitute of 



