300 BRITISH BEES. 



insects which I have captured in the course of my ento- 

 mological career. The fourth and the ninth species^ the 

 O. bicolor and 0. aurulenta, have very much the same 

 habitSj both usually burrowing in sandbanks, sometimes 

 however in wood, in which case the perforation, contrary 

 to the mode of wood-drilling bees, is made upwards, a 

 sagacity or instinct which saves it much trouble, for the 

 particles as they are removed by the mandibles are passed 

 beneath the insect, and their own gravity carries them 

 downwards, and thus the insect saves itself the labour of 

 conveying them out as they accumulate in inconvenient 

 quantities. The cells in this case are placed end to end. 

 When they burrow in the earth, the latter species often 

 associate gregariously in large numbers, and if they select 

 a cavity, instead of tunnelling it themselves, and it be 

 too large to take one cell upon the others, they form them 

 side by side, and thus fill the space. This is the case when 

 they adopt snail-shells as the receptacle for their incu- 

 nabula, and this is done by both these species, and the 

 shells they select are the empty ones of Helix nemoralis, 

 hortensis, and adspersa. The capacity of the latter shell 

 being much greater than that of the others, and too wide 

 for a single succession, she fills the interval by placing 

 them side by side, and with the increase of the whorl 

 of the shell towards its orifice she places them across the 

 space, and thus completes her task. In the former 

 shells, the cavity at first admits of the succession of but 

 one upon the other, but with its enlargement she places 

 them side by side, and this repeated fills the hollow. Its 

 aperture is then closed with earth and pebbles or sticks 

 agglutinated together, as described at the commence- 

 ment. The O.fulviventris burrows in wood, and upon 

 this species the Stelis phaoptera is parasitical ; and that 



