NOTES ON HYMENOPTERA. 



91 



it, a truth which teaches us that the study of Entomology is 

 inexhaustible; and we feel convinced that the complete his- 

 tory of a species has yet to be written. 



It is usual to place the Humble Bees in two divisions, one 

 containins^ such species as construct their nests on the surface 

 of the ground ; the second division, those that excavate, or 

 that take possession of some cavity underground. Such is 

 the general rule, but, like all rules, it has its exceptions ; 

 surface builders sometimes take possession of the nests of 

 birds, suspended in bushes, or attached to roofs or other parts 

 of buildings. 



Among the surface builders is ranked Bomhus sylvaruin; 

 last summer I noticed numbers of this bee frequenting a 

 clump of the dead-nettle, Laviium 2mrpureii7n, and being 

 anxious to find their nest, watched their homeward passage, 

 great was my surprise on seeing them enter a hole in the 

 ground, after the manner of Bomhus terrestris. This was 

 so interesting a circumstance, that I went the following day,. 

 provided with the necessary implements for digging out the 

 nest. It proved to be about a foot underground : the cavity 

 which contained the nest was about five inches in diameter, 

 and was lined with a mixture of dried moss and grass; the 

 community was small, there being seven females, six recently 

 disclosed, and the parent bee, whose wings were either worn 

 off, or had been clipped ofi' by the workers; there were 

 twenty-two males, and about forty workers; half-a-dozen 

 females were still undeveloped, as were also about twenty 

 workers. This is the first instance in which I have observed 

 a surface-building bee occupying an underground nest. 



During an entire month's collecting in Suffolk and Nor- 

 folk, I did not see a single surface-building Bomhus, except 

 B, sylvarumj whereas, in former years, I have seen them in 

 abundance. I ascertained, on inquiry, tliat the spring and 



