INTRODUCTORY REMARKS. ^^ 



MANDIBULA. This is the maxilla of Lin- 

 neus, and the present work, which professes to 

 adhere as much as possible to the Linnean 

 nomenclature. 



CLYPEUS. This term is equivalent with 

 labium of Linneus ; and denotes a part which, by 

 these insects, is used to answer the purposes of a 

 lip. Galea might, with equal propriety, be applied 

 to the dilated joint of the tarsus of Sphex clypeata, 

 as clypeus to this part. Fabricius, indeed, him- 

 self, as well as his disciple Panzer, in their de- 

 scriptions, have frequently used the term labium, 

 not to signify the Fabrician, but the Linnean 

 labium (b) ; of course 1 have employed this term 

 instead o{ cl7/peus(c). 



Having explained the terms employed by 

 Fabricius, I shall now proceed to consider his 

 characters of the class in question. When he 

 published his Genera Insectorum, he, at the same 

 time, constructed Natural Characters for the several 

 classes under which at that time he had arranged 

 them, but he neglected doing this for the new 

 classes which he has since formed. It is, however, 

 an excellent idea, and I mean to adopt it hereafter 

 with respect to the Hijmenoptera. Flis original 

 Essential Character of his Piezata class, as I ob- 



{l) The former in his Artificial Character oi Bemlex, and in 

 hl$ description of Hylceus cyllndricus, albilahisj &c. TIic 

 latter in Cralro and Nomada often. 



(c) Tab. 10. *it. c. 2, 5. fig. 12. and fig. 13. c. 



scned 



