104 Illinois State Laboratory of Natural History. 



joint of the outer ramus; those of the male with the 

 inner ramus 3-jointed and provided with phimose 

 hairs, as in the other legs. 



14 (15). Fifth pair of legs of female with the inner hairs of the 



last joint of the outer ramus transformed into short 

 thick spines. In the male, outer ramus of left leg of 

 fifth pair with two joints ; outer ramus of right leg with 

 three. Genus Osphranticum. 



15 (14). Fifth pair of legs of female with the inner hairs of 



the last joint of the outer ramus long and plumose. 

 Fifth pair of legs of male with both outer rami 2- jointed. 



Genus LiuDiocalanus. 



16 (9, 17). Abdomen of female 4- jointed, symmetrical. 



Antennte 25-jointed, articles 24 and 25 not confluent. 

 Four anterior pairs of feet generally with 3-segmented 

 rami, the fifth with 3-segmented outer and 2- or 3-seg- 

 mented inner ramus. Male antenna3 with segments 

 19-21 and 21-23 confluent. Fifth pair of feet sub- 

 chelate ; the right with 2-, the left with 3-segmented 

 rami. Subfamily Leuckartiina. 



17 (9,10). Abdomen 3- or 4-jointed, not always symmetrical. 



Four anterior pairs of feet with 3-jointed rami. Gen- 

 erally the left antenna of the male geniculate. Articles 

 19-21, 22 and 23 (or 22-25), and 1 and 2 confluent. 

 Fifth pair of legs with 3-segmented outer and 1-3- 

 segmented inner rami. Chela undeveloped or want- 

 ing. Subfamily Heteeoch.etina. 



18 (4). liostrum wanting. Fourth and fifth thoracic segments 



of female not confluent. Abdomen 3-segmented. Male 

 genital opening on the left ; right antenna prehensile, 

 segments 17 and 18, and 19 and 20 confluent. Inner 

 rami of fifth pair of feet Avanting ; outer ramus of left 

 foot 4-segmented, of right foot 3-segmented. Marine. 



Family Candacid^. 



19 (1). Division of body into anterior and posterior parts in 



front of the last (fifth) thoracic segment. This bears, 

 almost without exception, a more or less rudimentary 



