126 



AXXALS XEW YORK ACADEMY OF sCIEXCE-< 



^iromnent in a discussion of geographic distribution and yet it is almost 

 never taken tip in detail. There are several verv practical reasons for 

 this, two of which are well illustrated by this paper. First, there is 

 already such a mass of detail that it can scarcely be handled and, second, 

 the author is often, as in this case, ignorant of the ecological conditions 

 under which the species occur throughout their ranges. The importance 

 of ecological conditions may be illustrated in connection with what has 

 just gone before as well as with what follows. 



Fio. 4. — Ffeir near Bnfins San Vincente. Cuba 



The level area is rich agricultural land, and even the cliffs support a rather luxuriant 



vegetation. 



Air. Leng and myself went to Pinar del Eio, Cuba, chiefly to study the 

 ecological distribution of insects, ^'e collected spiders in a number of 

 environments, two of which are of interest here. South of the city is a 

 sandy plain which we studied fairly intensively between the nine and 

 thirteen kilometer posts on the road to Coloma. Leaving out of account 

 the really important local differences caused by ground water level and 

 the resulting differences in vegetation, figure 3 may be taken as fairly 

 typical of the region. Xorth of the city are the mountains and we col- 



