690 



FRESH-WATER BIOLOGY 



7 (8) Antennary expansion very large; no hepatic ceca. 



Latona setifera (O. F. Miiller) 1785. 



Antennules of both sexes alike, bent, with large, hairy flagellum set on at angle, looking like 



continuation of base. Color yellow; not transparent; old 9 often with briUiant colors in 



late autumn. Length, 9 , 2.0-3.0 mm. ; ^ , ca. i .5 mm. Widely distributed, but never abundant, 



among weeds in ponds and lakes. 



'//nm- 



MM. I. 



Fig. 1052. Latona setifera. 



8 (7) Antennary expansion small; hepatic ceca present. 



Latona parviremis Birge 1910. 



Antennule of 9 with basal part and long slender flagellum, like Latonopsis; of ^ very long, 

 like other Sididae. Color yellow. Length, 9' to 2.5 mm.; $ , 0.8 mm. Northern Wisconsin, 

 Michigan, Maine; in weedy waters of lake . 



Fig. 1053. Latona parviremis. 



9 (6) Without lateral expansion of antenna. . . 



10 



10(13) No spines on post-abdomen. . Diaphanosoma Yi'^chei i^s^ . . 11 

 No rostrum, fornix, or ocellus. Antennule small, truncated; olfactory setae terminal, with 

 slender flagellimi. Dorsal ramus of antennae 2-jointed; ventral 3-jointed. Claws with 3 basal 

 spines. $ with long antennule; copulatory organ; hook on first ''oot. 



