BEES AND THEIR ENEMIES. 115 



facets, seated upon a sort of footstalk. The man- 

 dibles are lancet-shaped and very acute, and the head, 

 by reason of the protuberant eyes, has very much the 

 shape of a dumb-bell. The antennae are branched, but 

 in Halictophagus, they are fiabellate. The thorax is 

 greatly developed ; the superior wing is like a rudi- 

 mentary wing-case, and is twisted, the inferior wings 

 are very lai-ge, and fold along the abdomen in repose 

 like a fan ; the legs are slender, and the tarsi with four 

 joints in Stylops, with three in Halictophagiis, and with 

 two in Elenchus ; the abdomen is long, very flexible, 

 and consists of eiglit segments. The insects themselves 

 do not exceed a quarter of an inch in length in the 

 largest, but they are generally very much smaller. The 

 perfect insect is very short-lived, not surviving many 

 hours, as just stated. They are usually found in the 

 months of May and June, and they have been dis- 

 covered to infest several species of Andrena and Ha- 

 lictus, for instance the A. nigro-cenea, upon which Mr. 

 Kirby first found it ; A. labialis, which I have frequently 

 caught stylopized ; A. rufitarsis, fulvicrus, Mouffetella, 

 tibialis, CoUinsonana, varians, picicornis, nana, parvula, 

 xanthura, convemuscula, Afzeliella, Gwynana, etc., and 

 upon Halictus (sratus, etc. 



The other mode of parasitism destructive to the bees is 

 where the parasite deposits its own egg upon the proven- 

 der stored by the bee for the sustenance of its own young. 

 The young of the parasite, either by being more speedily 

 hatched or more rapacious than the larva of the sitos, 

 starves the latter by consuming its food. This kind of 

 parasites consists of several Diptera, but they are mostly 

 bees which form a distinctive subsection of the family of 

 true bees [Apid<B), the subsection being called the 'Nudi- 



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