16-i NATURAL ARKANGEMENT OF INSECTS. 



,;he peculiarities of the natural history of which we 

 shall give in its proper place ; and it is also upon An^ 

 drena that the little hexapod creatures occur, called, we 

 think very correctly, Pediculi by Mr. Kirby, but which 

 have been asserted to be the larvae of Melo'e : the 

 correctness of this opinion we dispute ; but shall leave 

 the notice of our reasons for doing so until we arrive 

 at the Coleoptera. We are further acquainted with 

 many undescribed exotic forms among the Andrenid^B) 

 some of which are highly interesting. 



(14-7.) We now enter the division of the Apid^, or 

 genuine bees, where the diversities of form and struc- 

 ture are greater than in the preceding division, and 

 which consequently has given rise to a more extensive 

 subdivision into genera. It is, however, very probable, 

 judging from the contents of the collections which we 

 possess and have seen, that the species are not nume- 

 rically greater than in the Andrenidce. The Apidce re- 

 solve themselves very naturally into two subdivisions, 

 the solitary bees and social bees. The first of these sub- 

 divisions, the solitary bees, may be conveniently grouped 

 according to very obvious structural peculiarities, and 

 which, as usual, concur with the habits of the insects. 



(148.) We have. Firstly, the Andrenoides, or those 

 approaching, both in structure and habits, to the Andre- 

 nidce. These make their burrows in a similar way to 

 the typical portion of that group, and have their posterior 

 tarsi formed upon the same structural model : they also, 

 hke those insects, generally frequent syngenesious plants. 

 The most remarkable genera are Rophites, which has 

 the apex of the abdomen in the male denticulated be- 

 neath ; and Systropha, which in that sex has the ex- 

 tremity of the antennse very singularly curved. The 

 general structure of Nomada includes it better within 

 this group than Avith the other cuckoo bees, with which, 

 from habits, it might otherwise be associated. These 

 gay and wasplike insects are parasitical upon various 

 species of Andrena and Halictus, but one infests 

 Eucera. 



