on the Genus Coercba. 491 



Wlietliei* Paraguay should be included within these 

 southern limits it is impossible to say, but the records are 

 so far negative. 



Contained within the limits of this vast area, the genus is 

 commonly and universally distributed wherever the imme- 

 diate local conditions are favourable. Moreover, as regards 

 station, the representative species of the genus seem equally 

 at home, both on coral-islands, such as the Bahamas and 

 the Caymans, at virtual sea-level, or on forest-clad moun- 

 tainous heights which attain to an elevation of as much as 

 9000 feet iu the Peruvian Andes. 



In addition, however, to the exceptions already referred 

 to in the case of Yucatan, British Honduras, and Cuba, the 

 genus is not represented in the Galapagos or in the follow- 

 ing small Caribbean Islands: viz., Blanquilla, the Hermanos 

 Group, Islas de Avcs, and Orchilla (Leeward Islands, 

 Venezuela), or in Swan Island, which lies some hundred 

 miles to the north of Honduras, 



The absence of any species from the smaller islands 

 just mentioned, whether owing to adverse local conditions 

 or to distance and isolation from the mainland, is not very 

 surprising; but to the very interesting subject of the absence 

 of any species from Cuba we shall return. 



To anyone studying the many species which characterize 

 the genus Coereha there are certain outstanding features 

 which can hardly fail to be apparent. They may be 

 enumerated as follows : — 



(1) The striking contrast in mere depth of coloration 

 which characterizes insular species as compared with those 

 inhabiting the mainland. (C. luteula and C guianensis, 

 which are found along the northern limits of South America, 

 are, however, exceptions to this statement.) 



(2) The contrast in depth of coloration between the 

 pileuni and mantle characterizing all continental species 

 (except the two species just mentioned) as compared with 

 some uniform shade of black seen in these parts in all 

 insular species. 



(3) The relatively small amount of variation met with in 



