VI INTRODUCTORY REMARKS. 



Fab., and L. Andahisiaca, Rosenh.) ; and three others are, as to 

 their localities, doubtful. 



It thus appears that of the species contained in this volume, 



South America produces 228 



North America 9 



Africa 3 



Europe 2 



Doubtful • 3 



245 



and Asia and Australia none. 



Owing to the comparative rarity of all the species here described, 

 and consequently the paucity of them in collections, it is not easy to 

 assign to each its distinct geographical range ; very few appear to 

 be widely distributed ; each seems to have but the basin of a single 

 river, or one single island on the coast, or one range of mountains 

 as its sole locality ; and it is interesting to observe that the range of 

 the genera as well as that of the individual species appear to be (as a 

 rule) equally circumscribed. For example, the beautiful genus Mono- 

 platus has as yet been found only on the Organ Mountains and in 

 the neighbourhood of Rio Janeiro * ; the very distinct form of Ceri- 

 chrestus is met with only in the north of that continent, the Amazon, 

 and Cayenne ; the two European species of the genus Lithonoma, 

 found in Spain and Portugal, arc closely allied to each other ; and 

 although a third species of this genus has been discovered in Africa, 

 it was taken near Tangiers, on the immediately opposite coast of 

 the Straits of Gibraltar. 



On the other hand, however, instances are to be found where a 

 single genus appears to have a widely extended range. The genus 

 Loxoprosopus is represented in the province of Rio by L. ceramboides, 

 while, in the far-distant region of the Amazon, other species that 

 evidently belong to this same genus have been taken by Mr. Bates. 

 In a case like this, we may reasonably infer that other species of the 

 genus still have to be discovered in the vast central district of Brazil, 

 which will unite together these species geographically. 



* M. semiviolaceus is stated to be from Cayenne; but this, in my opinion, 

 seems to require to be substantiated. 



