1953] 
Young — Water Beetles 
25 
brackish water form, but from the situation cited blatchleyi 
will more likely be found associated with the ephemeral 
rain pools which form in the broadleaved evergreen jungle 
hammock associes of the Keys. It will probably also be 
found in the West Indies. 
Fig. 1. Lateral outline of aedeagus of holotype of Copelatus blatchleyi 
from Key Wesit, Florida. Fig.2. Lateral outline of aedeagus of Copelatus 
debilis from Brownsville, Texas. (Both figures drawn to same scale) 
Copelatus cubaensis Schaeffer (Jour. New York Ent. 
Soc., 16: 18, 1908) seems from the description to be very 
similar to blatchleyi, but is described as having a sub- 
marginal and six other striae on each elytron. A compari- 
son of the male genitalia should help to determine the re- 
lationships of several forms which we now place in differ- 
ent groups almost entirely on the number of striae on the 
elytra. The genitalia of debilis and blatchleyi are of a sim- 
ilar type radically different from those of glyphicus or 
chevrolati. C. chevrolati, the only other Copelatus so far 
taken at Key West, is easily distinguished from blatchleyi 
