244 THE ENTOMOLOGIST. 



months, until the warmth of returning spring calls them forth 

 to fulfil the object of their being. This history of their 

 economy has been recently spoken of as a plausible theory: 

 my own observation has long since convinced me that it is 

 simply one of those matters of fact that every one " who runs 

 may read " 



The Halicti are preyed upon by two species of fossorial 

 Hymenoptera, being carried off by them and stored up in 

 their cells as food for their own young : one of these de- 

 siroyers is Philanthus triangulum, which I observed at 

 Shanklin, in the Isle of Wight, conveying Halictus zonatus 

 to its burrows, although there can be no doubt of the hive 

 bee being its prey usually. The other fossor that attacks the 

 Halicti is Cerceris ornata ; it preys upon H. rubicundus, H. 

 zonuUis and H. cylindricus, female, for I never observed the 

 male bee selected for food. 



In my work on the ' British Bees,' published in 1855, 

 twenty-six species are described ; by some accident the 

 description of Halictus villosulus was omitted: the number 

 of known species is now twenty-eight, an additional one 

 having been since discovered. In a genus, the discrimi- 

 nation of the species of which is a difficulty of no ordinary 

 kind, 1 think it advisable to separate the species into 

 sections : this is not only advisable under such circum- 

 stances, but it may be deemed also necessary in consequence 

 of one division having a somewhat different neuration in the 

 anterior wings : were a strict adherence to the wing or alary 

 system pursued, the last division might appropriately be 

 raised to the rank of a separate genus. In the present revision 

 I have, however, adopted a different system of arrangement: 

 this is simply for the purpose of rendering the task of inves- 

 tigation easier to the student : I give at the end of the 

 revision a list of the species in the order in which I think 

 they group most naturally. 



Some authors have adopted the generic name of Hylaeus 

 for these bees, but Fabricius, who established the genus, did 

 not characterize these insects, but instituted the genus Hy- 

 laius apparently lor the reception of a nimiber of elongate 

 bees, without much regard to their characteristic distinctions, 

 so that we find it a receptacle for Andrenida; as well as for 

 true Apidae ; I therefore retain Latreille's generic name 



