ENTOMOSTEACA OF MINNESOTA. 245 



meshes. Post-abdomen short and wide, rounded at the end, orna- 

 mented by seven or eight chisters of minute spines behind as well as a 

 lateral row of scales. Length 0.43 mm. 



Hellich says the pigment fleck is larger than the eye and is farther 

 from the end of the beak than from the eye. 



Alona piilchra Hellich. 

 Sars '61 (rectangula and lineata); Hellich '74 and '77 (lineata); Matile '90. 



We are influenced by Matile in not recognizing A. lineata Fischer 

 and substituting Hellich's name. Alona lineata of Kurz is said by 

 Matile to be A. costata Sars. 



Body small, elongate oval, truncate behind and of a pale color. 

 Greatest height near the middle. The upper margin is rounded, the 

 lower one somewhat sinuate, with setse of moderate length. The beak 

 is short, reaching nearly to the level of the lower margin of the shelly 

 the pigment fleck is one half the size of the eye, to which it is much 

 nearer than to the end of the beak. Post abdomen short, broad and 

 tapering toward the end, truncate, armed with seven to eight large 

 teeth; short caudal claws with a small basal tooth. Shell marked 

 with distinct lines running horizontally. The ephippial females are 

 recognized by a deep color and the greater elevation of the back 

 Length 3.8 to 4.00 mm. 



I am unable to satisfactorily differentiate the species of this group. 



* Alona costata Sars. 

 Plate LX, Fig. 3. 



Alona lineata — Schoedler, Kurz, P. E. Mueller. 

 Alona modesta — Herrick. 



We need not attempt to unravel the perplexing synonomy. As 

 thus defined the species seems to be common in Europe and America. 

 Shell quadrangular, widest behind the middle. Beak of moderate 

 length. Pigment fleck smaller than the eye and midway between eye 

 and beak. Antennae with only seven setre. Labrum small. The shell 

 is strongly and coarsely striped parallel to the shell margins. Lower 

 margin straight or concave, armed with rigid setse. Coecum long. 

 Post-abdomen rather short, acute and excavated at the distal end. 

 Anal spines nine or ten, equal, with a secondary series of scales. 

 Claws smooth, except for a basal spine. Length 0.55 to 0.65 mm. The 

 claw of the male lacks the basal spine. 



The Minnesota representative of this widely distributed species 

 differs in some respects. The lower margin is nearly straight and 



