BEES ANDRENIDES 



25 



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 

 generations of the same species may vary. 

 Verhoeff has described the bm-rows of 

 Halictus c[imdricinctus 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.— Nestin 

 the shaft. The larvae that are present 

 in the brood-chambers at any one 

 moment differ much in their ages, a 

 fact that throws some doubt on 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. Verhoeff states that many of the 

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

 be the most deadly of the enemies of Aculeate Hymenoptera. 

 The nest of Halictus maculat^is has also been briefly described 

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

 that of H. quadricinctus. 



The genus Andrcna 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 bvirrows in the 

 ground, preferring sandy places, but frequently selecting a gravel 

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



of Halictus 

 quadricinctus. u, Original 

 burrow, with entrance e 

 thereto ; n, retreat or con- 

 tinuation of the burrow ; u\ 

 the vaults ; s, the accumula- 

 tion of cells. (After Ver- 

 hoeff, Verh. Ver. Rheinl. xlviii. 

 1891 ; scale not mentioned.) 



