ANTHOPHORA. 239 



more regularly to the ordinary type of structure. The 

 first section also nidificate gregariously, forming enor- 

 mous colonies which consist of many hundreds ; whereas 

 the second are solitary nidificators, and at most half-a- 

 dozen may be found within as many square yards of 

 territory, and one species, the A.farcata, diverges con- 

 siderably from the ordinary habits of the genus, and 

 closely approaches those of the foreign genus Xylocopa, 

 but its structure necessarily retains it within the boun- 

 daries of the genus. All these insects exhibit the pecu- 

 liar characteristic of the Scopulipedes, in the insertion of 

 the second joint of the posterior tarsi at the very bottom 

 of their plantse, conjunctively with the polliniferous 

 scopa, placed externally upon their tibiae and plantae, in 

 which characteristics the Andrenoid Macropis remark- 

 ably resembles them, and which I have noticed in my 

 remarks upon that genus. 



The first section burrows in banks, where their colo- 

 nies are extremely numerous. In the tunnels which 

 they form they construct several elliptical cells which 

 they line with a delicate membrane of a white colour, 

 formed by a secretion or saliva derived from the di- 

 gestion of either the pollen or the honey which they 

 consume. Each cell when formed is stored as usual, 

 and the egg deposited, and then it is closed. There is 

 but little variation in these processes among all the 

 solitary bees, excepting in the case of the artisan bees 

 and the more elaborate processes of Colletes, in which, 

 however, the casing is merely thicker, arising from 

 several layers of the coating membrane. The perfect 

 insects make their appearance during the spring and 

 summer months, their successive maturity being the 

 result of the previous summer and autumn deposit of 



