254 Timehri. 
The characteristic legs of S. guianense readily distinguished it from S. tarsale. 
Williston describes the latter as follows :— 
“* Legs reddish yellow ; tarsi black except that the proximal half of the 
middle and hind metatarsus are light yellow ; first and third joints of the 
first pair each with two long hairs; second and third joints of the same 
pair dilated, fourth and fifth very small. Hind metatarsus elongate and 
stout, the following two joints a little dilated the fourth and fifth small.” 
I have to acknowledge my great indebtedness to Dr. Q. B. de Freitas of 
Berbice for his great kindness in translating the necessary parts of Dr. Goeldi’s 
work, 
ILLUSTRATIONS: 
Fig. 1. Diagram of thoracic markings of Simulium amazonicum, Mole. 
Fig. 2. Diagram of thoracic markings of Simulium amazonicum. Female. 
Diagram of wing venation of Simulium guianense. 
