28 Mr. D. Sliarp'^j Contributions to the 



regions, arc comparatively less frequent in the tropics and 

 are there re])laced by the brilliant and magnificent forms 

 ■which at present represent the insects of the tropics in 

 our collections. I am myself, however, of opinion that 

 obscure and minute species of insects are quite as abun- 

 dant in the trojjics as they are in temperate regions, and 

 that the real ditlerence that exists between the tropical 

 and cooler regions of the -world in this respect is, that in 

 the tropics these minute insects are accompanied by a 

 large number of brilliant and massive forms, which dis- 

 appear gradually as the cold regions are approached. The 

 following (juotatiun Avill show that the removal of such 

 misconceptions is of importance. In Lyelfs " Students' 

 Elements of Geology,*' that very careful author, in alluding 

 to the remains of numerous species of insects found in the 

 limestone of the Lias, in Gloucestershire, says (p. 342): — 

 " The size of the species is usually small, and such as 

 taken alone Avould imply a tempei'ate climate, but many 

 of the associated organic remains of other classes must 

 lead to a different conclusion." 



If my estimate of the abundance of obscure forms in 

 the tropics be correct, the discrepancy alluded to by Sir 

 Charles Lyell, in the passage just quoted, between the 

 evidence from insect and that from other classes, would 

 be considerably reduced, if not entirely removed. I need 

 not, however, insist on this jioint, for now that -we have 

 obtained a considerable knowledge of the more striking 

 insect forms of the tropics, we are constantly having 

 revealed to us glimpses of the enormous number of minute 

 species which probably exist there ; I may, however, indi- 

 cate Mr. Wollaston's important work on the Cossonidce 

 recently published by the Society, as illustrative of the 

 correctness of my estimate. 



Tiu-ning now to the number of species from the 

 Amazons, it will be seen that the number here emunerated 

 is 487, of which 463 are described as new. The propor- 

 tion of new species to those previously described is there- 

 fore about as 19"1. This very large proportion of new 

 species suggests forcibly how nearly complete is our want 

 of knowledge of the Stuplu/linidcc of tropical America ; 

 nevertheless a good number of JNIexican species have been 

 described by Fauvel and Solsky, and latterly several 

 species from Peru have been made known by the latter of 

 these savants ; the most important contribution to a know- 



