THE GYMNOTID EELS OF TROPICAL AMERICA. 



171 



viduals these were supplemented by large Crustacea and small fishes. As this fish 

 is known to frequent the weeds of the small open streams and trenches, it is prob- 

 able, judging from the nature of its food, that it does most of its feeding at or near 

 the surface. 



Eigenmannia virescens (Valenciennes). 



Snout short and rather blunt; minute teeth in patches in both jaws; mouth 

 small; not exceeding 300 mm. in lengtli. 



In the twenty-three stomachs examined the bulk of the food was of two 

 kinds, regardless of the size of the fish, namely Entomostraca and the larvae of 

 insects. These two kinds of food exceeded all others not only in numbers but in 

 bulk. The only kinds of food found in any amount were Hydrachnidae and Anne- 

 lida. All of the food is soft and small. The four classes of food are found distrib- 

 uted throughout the table, but there is a grouping with regard to the size of the 

 fish. Over one-half of the eighteen hundred and seventeen Entomostraca were 

 taken from specimens under 200 mm. long, and more than one-half of the insect 

 larvae from the specimens over 200 mm. The other kinds of food were also found 

 in the stomachs of specimens over 200 mm. long. The young fish are restricted 

 to entomostraca more than the adults. The insect larvae were for the most part 

 small Diptera, and the Annelida represented a small soft form resembling Tubifex. 



(3) Eigenmannia macrops (Boulenger). 



Snout short, truncated; teeth minute; in patches in both jaws; mouth quite 

 small; size small, not exceeding 200 mm. 



Only adult specimens of this species were examined, so no comparison of the 

 food and the size of the fish could be made. The food of this small species seemed 

 much the same as that of specimens of E. virescens of the same size. Entomostraca 

 and insect larvae formed the bulk of it. 



