BEES ANDRENIDES 



June " ; then there was an interval, and in the middle of August 

 males began to appear, followed in ten 

 or twelve days by females. Hence it is \/ 

 probable that in different countries the 

 times of appearance and the number of . ; -.\% : --.f^~'V'~r^f 



generations of the same species may vary. /^ 7 | 



Yerhoeff has described the burrows of 

 Halictus quadricinctus with some detail. 

 The cells, instead of being distributed 

 as usual throughout the length of the 

 burrow one by one, are accumulated 

 into a mass placed in a vault communi- 

 cating with the shaft. This shaft is 

 continued downwards to a depth of 10 

 cm., and forms a retreat for the bees 

 when engaged in construction. Several 

 advantages are secured by this method, 

 especially better ventilation, and pro- 

 tection from any water that may enter FIG. 12. Nesting of 

 the shaft. The larvae that are present ^T^h ^Tl 

 in the brood-chambers at any one 

 moment differ much in their ages, a 

 fact that throws some doubt 011 the 

 supposed parthenogenetic generation. 

 No cocoons are formed by these Halictus, 



the polished interior of the cell being a sufficiently refined resting 

 place for metamorphosis. Yerhoeff states that many of the 

 larvae are destroyed by mouldiness ; this indeed, he considers to 

 lie the most deadly of the enemies of Aculeate Hymenoptera. 

 The nest of Halictus maculatus has also been briefly described 

 by Yerhoeff, and is a very poor construction in comparison with 

 that of H. quadricinctus. 



The genus Andrena includes a great number of species, 

 Britain possessing about fifty. They may be described in a 

 general manner as Insects much resembling the honey-bee 

 for which, indeed, they are frequently mistaken but usually a 

 little smaller in size. Many of the bees we see in spring, in 

 March or April, are of this genus. They live in burrows in the 

 ground, preferring sandy places, but frequently selecting a gravel 

 path as the locality for their operations ; they nearly always live 



thereto ; n, retreat or con- 

 tinuation of the burrow ; w, 

 the vaults ; s, the accumula- 

 tion of cells. (After Ver- 

 hoeff, Verh. Ver. Rheinl. xlviii. 

 1891 ; scale not mentioned.) 



