200 



upper oue very small, and the middle and lower one large and nearly 

 equal in size. 



On turning to the New-World species of the genus, we find four 

 variations in the dentition of the mandihles ; the group of pale spe- 

 cies typified by 31. cequinoctialis, Dej. {bifasciata, Brulle), corre- 

 sponds almost identically in the dentition of both sexes with the old 

 type {M. senegalensis), as described above, the right mandible having 

 two equal-sized large acute teeth in the middle of the inner margin, 

 and the left one also two, the upper one being very small. For this 

 group I have proposed the subgeneric name of Ammosia, in allu- 

 sion to their habits, which differ materially from those of the other 

 species. 



A black-coloured species from South America {M. sepulchralis, 

 Fabr., M. variolosa, Dej.) differs from the Ammosice in the left man- 

 dible, while the inner margin has only oue tooth in the middle, of 

 considerable size, and exhibiting on its under side a minute tooth, 

 being all that remains of the large middle tooth of the left mandible 

 of the Ammosia. This species is the type of Mr. Hope's subgenus 

 Anaira. 



Another very fine Brazilian species {M. testudinea, King) differs 

 in the dentition of the sexes in a more striking manner than any of 

 the preceding. The right mandible of the male is long and sickle- 

 shaped, with a small tooth obliquely truncated below the middle of 

 the inner margin, and between this and the tip of the jaw is a mi- 

 nute acute tooth. The left mandible has two teeth on the inner 

 margin above the middle, the lower one broad and acute, but rather 

 obliquely truncate, whilst the upper one is very small. The right 

 mandible of the female, on the contrary, has two very large equal- 

 sized teeth in the middle of the inner margin, whereas the left jaw in 

 this sex is quite similar to that of the male. 



There still remains a numerous group of American species (the 

 type of which is Cic. Carolina, Linn.), which differ from the rest of 

 their continental brethren in possessing three teeth in the middle of 

 the inner margin of each jaw, tlius resembling the Australian species 

 above noticed, and hence I proposed the name of Tetracha, or four- 

 toothed, for this group, counting the acute apical portion of the man- 

 dible as a fourth tooth. In general, in both sexes, the tooth next 

 below the apex of the jaw is equal in size to, or even larger than, the 

 apical part or tooth itself (thus differing from the Australasian spe- 

 cies), and the middle of the three teeth is smaller than the rest ; but 

 in the left mandible in the males the tooth below the apical tooth is 

 even still larger, whilst the middle tooth is much smaller, and the lower 

 tooth is quite minute. In the female, on the contrary, the middle 

 one of the three teeth of the inner margin is rather larger than the 

 upper one (which is only of a moderate size), and the lower one is 

 small. 



From these particulars (united with the peculiarities of colouring, 

 geographical range and habits of the species) we are enabled to pro- 

 pose well-founded subgenera, a task which has hitherto been con- 

 sidered hopeless in the genera of Cicindelidce. The Old- World spe- 



