new Sub- Genus of Exotic Hemipterous Insects. 29 



Antennce articulo Imo crassiori, duobus proximis minutis, ul- 

 timo magno ovali. 



Prothorax postice parum elevatus, at multum dilatatus, angulis 

 posticis acutis porrectis, parum retro directis, dorso tricari- 

 natus. 



Scutellum mediocre, ad medium abdominis attingens, planum, 

 apice rotundatum. 



Hemehjtra ad apicem abdominis attingentia, membrana api- 

 cali maxima venis 5 longitudinalibus, postice oblique connexis, 

 duabus internis ad angulum internum ai'eolam rotundatam 

 efficientibus. (PI. 2, fig. So.) 



Abdomen planum, latissimum, rhombiforme, thorace duplo la- 

 tins, lateribus hemelytris baud obtectis. 



Pedes antici raptorii ut in Macrocephalo, at magis elongati, pos- 

 tici 4 breves simplices. 



I do not know tbat any rule bas bitberto been proposed for tbe 

 regulation of tbe nomenclature of sub-genera. Is it, for instance, 

 determined wbetber, in cutting up a genus into suh-genera, tbe same 

 rule sbould be preserved as in cutting up an o\d. family-genus mio 

 genera, namely, that the old generic name should also be still 

 employed, subgener'ically, for the typical sub-genus? Dr. Hors- 

 field, in the Lepidoptera Javanica, and other subsequent authors, 

 have adopted this plan, giving the typical species of Thecla (for 

 instance) as forming the sub-genus " Thecla, stride sic dicta." 

 Mr. Robert Brown has pursued a different plan. His rule is to 

 give to the inferior groups a cognomen, introduced parentheti- 

 cally between the generic and trivial names. Thus, taking his 

 own illustration, given in the botanical appendix to the Narra- 

 tive of Travels and Discoveries in Northern and Central Africa, 

 Cleome pentaphylla, which is the species on which the genus 

 was chiefly founded, but which has an aestivation so remarkable, 

 that it might constitute a separate sub-genus, to be named 

 Gymnogonia, should have its names thus expressed, Cleome (Gym- 

 nogonia) pentaphylla. By thus employing the sub-generic name, 

 the principal group would be kept in view, whilst its subdivisions 

 would be carried to the same extent, and the subordinate groups 

 as well expressed as if they had been actually separated into 

 distinct genera. 



In this manner of treating the names it will be seen that the 

 typical species of the old genus receives a subgeneric name dis- 

 tinct from its generic. And it is in this manner that Mr. M'Leay 



