28 Mr. D. Sharp's Contributions to the 



regions, arc comparatively less frcrpicnt in the tropics anrl 

 are there rc])]acecl by the brilliant and magnificent forms 

 Avhich at present repi'csent the insects of the tropics in 

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

 obscure and minute species of insects are rpiitc as abun- 

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

 that the real diffei'cnce that exists between the tropical 

 and cooler regions of the Avorld 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 quotation will show^ that the removal of such 

 misconceptions is of importance. In Lycll's " Students' 

 Elements of Geology," that very careful author, in alluding 

 to the remains of mimcrous 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 would imply a temperate 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 knowledire of the more striking 

 insect forms of the tropics, we arc constantly having 

 revealed to us glimpses of the enormous number of minute 

 species which ])rol)al)ly exist there; I may, however, indi- 

 cate I\Ir. A\'()llastun's important work on the Cossonidcc 

 recently published by the Society, as illustrative of the 

 correctness of my estimate. 



Turning now^ to the number of species from the 

 Amazons, it will be seen that the number here enumerated 

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

 tion of new sj)ccics to those previously described is there- 

 fore about as 19"1. This very large ])ro])ortion of new 

 sj^ecies suggests forcibly how nearly comj)k'te is our want 

 of knowledge of the Staji/ii/liiiidce of tropical America ; 

 nevertheless a good munber of jNIexican species have been 

 described bv Fauvcl and Solskv, and latterly several 

 S])ccies from Pei-u have been made known by the latter of 

 these savants; the most important contribution to a know-- 



