KEY TO THE ENTOMOSTRACA OF COLORADO 



283 



69 (38) Both branches of antenna 3-jointed. 



70 (71) 



73 



Intestine convoluted. 



Family Chydoridae 70 

 Anus terminal. Post-abdomen very broad and flattened; armed with 

 more than 100 close-set teeth on dorsal 

 margin. Two caecae at anterior end 

 of gut. . . Genus Enrycerus 



One species in United States. 

 Length, 3.0 mm. 



Eurycertis lamellatits (O.F.M.) 



Tolland, Twin Lakes region; 8,100-10,800 ft. (North- 

 ern parts of United. States and Europe. A northern and 

 alpine form.] 



71 (70) Anus not terminal but on dorsal 

 margin. Post-abdomen usually narrow 

 and armed with spines or tufts of 

 bristles, or both, on post-anal por- 

 tion 72 



72 (77) Abdominal claw, in addition to 

 the usual basal spine, has a second small one near the middle. . . 73 

 (76) Head distinctly keeled, i.e., the eye is remote from margin of head. 



Beak short and blunt 74 



(75) Post-abdomen very long and narrow; armed with about 20 spines and 

 a corresponding number of tufts of fine bristles. . Genus Camplocercus 



One sp)ecies in Colorado. Length, i . o mm. 



Camplocercus reclirostris Schoedler 



Fig. 42. — Eurycerus lamellatus. 



ToUand,TwinLalies; about g.c 

 north or south.] 



) ft. [Common in America and in Europe but probably not in extreme 



Fig. 43. — Camplocercus recti- 

 roslris. 



Fig. 44. — Acroperus harpof. 



Fig. 45. — Kurzialatissima. (After 

 Birge.) 



7S (74) Post-abdomen not extremely narrow; armed with a row of about 12 



tufts of bristles. Genus Acroperus 



One species in Colorado. Length, 0.8 mm. Acroperus harpae Baiid 



Tolland; 8,100-10,000 ft. [Common in United States and in northern Europe.] 



