1034 Wisconsin Academy of Sciences, Arts, and Letters. 
moderately long, set on small papillae placed widely apart. 
Claws with large base, somewhat curved, with 2 basal spines 
and denticulate. Eye of, moderate size, near dorsum of head; 
optic nerve very long, macula nigra present. 
Simple copulatory organs in male. First foot without 
hook, resembling female. 
On the whole, this genus seems to he northern in its habitat. 
Latonopsis is more abundant in southern and tropical regions, 
though by no means confined to them, while Pseudosida seems 
to belong to warm countries exclusively. 
Species. 
1. L. setifera (0. E. Muller) 
Antennule with very short, stout basal part, large flagellum 
set on at an angle and appearing as continuation of base so 
that the antennule is angulated. Olfactory setae on posterior 
side of base, very small. Flagellum thickly set with long 
slender hairs. Expansion of basal joint of dorsal ramus of 
antenna very large. Setae about 11 ~~ ^ 0 f somewhat un- 
equal length. Spines 5^y~5’ that on ventral ramus large. 
Intestine with small anterior prolongation. Sixth foot with¬ 
out branchial sac. Antennule of male similar in general to 
that of female, but with a ciliated sensory seta on inner side 
of basal part. Color yellow, not transparent. The old fe¬ 
male often has brilliant colors in late summer. 
Length of female, 2.0-3.0 mm.; male, about 1.5 mm. 
In ponds and lakes among weeds in shallow water; widely 
distributed but not very abundant anywhere. Males appear 
in August or September. 
This species has been found in northern Europe, including 
Russia and Austria. It is said to he absent from France 
and southern Europe. In the United States it has not been 
found as yet on the Pacific coast, hut is present in all other 
regions. I have specimens from Baton Rouge, Louisiana, so 
that it extends to the Gulf coast. 
