NORTH AMERICAN SPECIES OF THE GENUS ATAX 229 



It is present in the material from Illinois in TJ. alatus, TJ. 

 asperrim us, TJ. cormdus, TJ. gracilis, TJ. picstulosus, TJ. pUca- 

 tus and TJ. occidens from the Illinois river at Havana, and 

 from TJ. gracilis, TJ. levissimus, TJ. lachrymosus, TJ. jmstulosus 

 and TJ. tuberculatus from the Spoon River at Duncan's Mills 

 and Bernadotte. Also in material from the Cedar River at 

 Mt. Yernon, Iowa, from TJ. rectus, TJ. alatus and others. 



In New York it has been found at Chautauqua Lake in TJ. 

 luteolus and at Cheektowaga, Erie County, in TJ. occidens. 



9. Atax stricta Wolcott. 



Atax stricta Wolcott, 98, 283. 



Very similar to the preceding in ruany ways but differing in details. 

 It is smaller than A. fossulatus, relatively broader and the legs are not 

 only slenderer and shorter, but have usually a blue tinge which is lacking 

 in the other species. 



Eyes small and rather distant from one another. 



Maxillary shield and mandibles very similar to those of A. fossulatus. 



Palpi slenderer than those of that species and with the last segment 

 somewhat more strongly curved; ventral papillae on 4 relatively a little 

 more prominent. 



Epimera in general of the same form. They are, however, slightly 

 broader proportionately, and the posterior median angle of IV is more 

 rounded and not so strongly excavated. 



Legs relatively shorter, more slender and not so tapering as those of 

 the preceding species. I, not so noticeably stouter than the others and distal 

 segment, instead of growing constantly smaller toward the tip, is nar- 

 rowed in the middle and dilated at the tip, which is even slightly broader 

 than the base. As in A. fossulatus, 5 is relatively elongated on III and 

 both 5 and 6 on the last pair of legs, and as in that species III is longer 

 than II. Distal segments l'elatively longer on all legs and last segment 

 flattened and very slightly dilated dorso-ventrally at the tip, instead of 

 gradually contracted as in A. fossulatus. Claws all simple, relatively 

 longer and more slender, and those on I stouter and not so evenly curved 

 as those of the other legs. Not so many spines on the legs as in the allied 

 form, but they are longer. 



Genital area in about the same position as in the preceding but rela- 

 tively smaller, the acetabula smaller, and intead of the last two being side 

 by side they are all in one curved line. The two rows do not approach 

 each other so closely anteriorly and posteriorly as in the other species. 

 The sexes differ in a manner similar to those of A. fossulatus. 



