740 Insects. 



banks. Mr. Kirby has recorded his having captured it in sand and 

 chalk pits. 



Osmia hirta I have repeatedly observed at Battersea, entering its 

 burrows in posts and rails, into which I also observed, on more than 

 one occasion, Stelis aterrima enter. I have little doubt the latter is 

 parasitic on the Osmia. This species also excavates bramble-sticks ; 

 a friend has bred it from them, and has furnished me with one of the 

 sticks. The cells are similarly formed to those of O. leucomelana, 

 and have similar divisions between them. 



Osmia cserulescens burrows in posts and rails, in brick walls, — 

 choosing those bricks which are softest and most easily perforated, — 

 in the mortar of walls, and in hard sand-banks. I have observed Ste- 

 lis aterrima entering its nests. 



Osmia tunensis varies in its choice of situations ; sometimes, as de- 

 tailed above, availing itself of the spiral tube of a snail-shell, at others 

 choosing posts, boards, or rails, and not uncommonly the perpendi- 

 cular side of a hard sand-bank. 



Osmia bicornis is a bee of varied habit ; it sometimes constructs its 

 burrows in brick walls that are soft and crumbling, or in the mortar 

 of stone walls ; at other times in posts, rails, or decaying trees. I 

 have observed it in multitudes entering its burrows in an old decay- 

 ing willow tree. It sometimes avails itself of ready-formed tubes, as 

 I once found it entering the stems of some reeds used in thatching an 

 out-house on Wimbledon-common. It is commonly found in com- 

 pany with Anthophora retusa, constructing its tunnels in the same 

 bank. 



Osmia bicolor, as before stated, breeds in shells, but commonly 

 burrows in banks ; I have observed it doing so at Purfleet in Essex, 

 and Greenhithe in Kent. 



Osmia atricapilla. This species constructs cells of mud, upon the 

 nearly perpendicular sides of banks, where the soil is of a light nature. 

 Last year I found five of these cells on a bank under a tuft of grass, 

 near Birch-wood, Kent. In a previous number (Zool. 403) will be 

 found an excellent description of the nests of this bee, by Mr. G. R. 

 Waterhouse. 



The above details show the truly remarkable power possessed by 

 these bees of varying their economy in accordance with accidental 

 circumstances. We may well enquire, By what faculty does the bee 

 ascertain that the spiral tube of a snail-shell is so well adapted to her 

 purpose as to supersede the necessity of laboriously excavating a wall, 

 a rail, or a sand-bank ? Truly, in the words of Kirby, it is the teach- 



