210 BEES OF GREAT BRITAIN. 



they acquire the gay livery in which we are in the habit of seeing 

 them when on the wing. 



The females and males do not appear before the season is con- 

 siderably advanced, differing in the precise time in the various 

 species : the males of B. pratorum appear first these begin to 

 come forth about the third week in May, The connexion of 

 the sexes of these bees being very rarely observed, I am inclined 

 to believe that it usually takes place in the nest ; pairs of several 

 species have however been captured under these circumstances ; 

 thus, independent of rearing them from their nests, giving addi- 

 tional evidence of their being correctly united. 



The males after once leaving the nest seldom return to it, but 

 I have several times observed them re-entering it, and by this 

 means have discovered their colonies : and Mr. Kirby states that 

 he once saw the male of E. lapidarius entering the nidus of that 

 species. 



The nests of the Eombi are infested with several insects which 

 devour the wax and honey, and by others which devour the 

 young brood ; most nests swarm with a species of Acarus, which 

 devours the wax and honey ; the larvae of Tinea pellionella also 

 abound in many: nests, they were found in great numbers in 

 that of B. Derhamellus ; in the same nest was also found An- 

 therophayus glaber and Anobium paniceum : some communities 

 are much infested with the larvae of Volucella. 



The Bombi have also a parasitic genus of bees which inhabit 

 their nests, apparently occupying a state of aristocratic inde- 

 pendence in the community ; whether they take any part in the 

 economy of the community has not been ascertained. These bees 

 were first observed by Mr. Kirby ; he noticed that four of the 

 Bombinatrices had no corbicula for conveying pollen to their 

 nests, and proposed a division for these Humble-bees, whose eco- 

 nomy he conjectured must be different from that of the rest of 

 the family. Although the parasitic connexion existing between 

 these and the true Bombi has been long conjectured, no author 

 has hitherto found them in the nests of the working species ; 

 although I have taken or examined a very large number of the 

 nests of Bombus, I have only occasionally met with the parasites 

 in them ; but never in the nests of the brown Humble-bees. 

 Apathus Barbutellus was found in the nest of Bombus pratorum 

 and Bombus Derhamellus, but many nests do not contain para- 

 sites. Apathus nemorum occurs in the nest of Bombus terrestris, 

 and it probably also frequents that of B. subterraneus. What 

 office these bees perform in the economy of the nest has not been 

 discovered ; they live on the most friendly terms with the in- 

 dustrious part of the community, and it is probable that upon 

 them devolves some important office, the nature of which it 



