a large Heliconine collection made in French Guiana. 353 



iii id west of the Saramacca River in Dutch Guiana. Also 

 the almost totally unexplored country entomologically 

 between the Oyapock River on the eastern boundary of 

 French Guiana and the mouth of the Amazon. 



It will be seen on reference to the sketch map that the 

 mountain range that borders the interior boundary of the 

 Guianas descends on the boundary of Dutch Guiana to 

 500 ft., while to the east and west it rises to the neighbour- 

 hood of 3,000 ft. It is thus understandable how the 

 variable Heliconine forms can extend across Brazilian 

 Guiana to the north bank of the Amazon at Obydos. It 

 is still to be discovered why the variable melpomene and 

 erato should not be found in British Guiana, especially in 

 the region of the Berbice River or the Corentyn River, as 

 there do not seem to be any physical barriers. The 

 climate one would suppose also to be substantially the 

 same. There may be differences in the seasons. In 

 British Guiana there are two wet and two dry seasons 

 over a large area. We cannot get information about 

 French or Dutch Guiana in this respect, but at Para 

 there is one long wet and one dry season. From the 

 general climatic standpoint there is great uniformity, heat 

 and moisture prevailing with great uniformity throughout 

 the year, and even if no rain falls for two months the air 

 is always heavy with moisture, and very heavy dews are 

 deposited at night. 



March 29, 1919. 



