On the Geographical Distribution of Insects. 235 



appears to have a special entomological Fauna, in which the 

 Melanomas are dominant. Mexico properly so called, pre- 

 sents every kind of climate and vegetation, from the vparm 

 lands {tierras calientes), which form a zone of several leagues 

 in breadth, to the cold lands [tierras frias), where almost a 

 perpetual snow prevails. The shores of the Gulf of Mexico 

 are almost the only part that has been explored, and it is 

 extremely rich, presenting, besides many peculiar genera, a 

 multitude of species belonging to the genera of Brazil and 

 Guiana. Central America is scarcely known. 



28th, The Antilles. This Archipelago, forming an arc be- 

 tween North and South America, is connected with both by its 

 entomology. We again meet with many species of the main- 

 land, and of the United States ; but the large islands have 

 also their appropriate insects. Papilio Ljcoreus, and P. Imerius, 

 for example, have hitherto been found only at Hayti ; Nym- 

 phaUs Rogeri at Cuba ; Scarabaeus Hercules exists in the 

 greater pai-t of the Archipelago, &c. The smaller isles, on 

 the contrary, appear very poor. The most interesting dis- 

 covery made of late years in this Archipelago is that of a true 

 species of Carabus, which has lately been found at Porto Rico. 



29th, Valley of the Bio Magdalena, and that of the Lake 

 Maracaybo, including the Andes which separate them. This 

 region, which has been but little examined, is particularly 

 rich in Coleoptera ; although its species belong in general to 

 tlie same genera as those of Guiana, they are all different. In 

 the number appears a Scaraba?us as large as S. Hercules, and 

 nearly related to it, but altogether distinct. No other place 

 ha£ hitherto afforded the line genus Psalidognathus. Its Le- 

 pidoptera have some affinity with those of the Antilles, but 

 many of them are exclusively appropriated to this region, 



30th, Province of Caraccas, from the sea of the Antilles to 

 the Orinoco on the south. We are acquainted only with a 

 few Lepidoptera, which are very distinct from those of Gui- 

 ana. The Llanos, which extend towards the south, are un- 

 known in their entomological relations, but they must be very 

 unproductive. 



31st, Guiana, comprehending under that name all the ter- 

 ritory comprised between the Orinoco, the Rio Negro, the 



