DACTYLOPUS. 105 



prehensile, first or second joint of the outer branch 

 elongated ; second, third, and fourth pairs with both 

 branches 3-jointed ; fifth pair 2-jointed and usually 

 foliaceous. One ovisac. 



The genera belonging to this sub-family are Dacty- 

 lopus, Thalestris, Westwoodia, Ilyopsyllus (?), Harpac- 

 ticus, Zaus, and Peltidium. The genus Ilyopsyllus is 

 included provisionally only in this group ; its struc- 

 ture has not been fully made out, but the abnormal 

 form of the mandibles and antennae will probably 

 necessitate its removal to some other position. 



Diagnosis of Genera of Harpacticince. 



(~ f two joints Harpacticus. 



three ("greatly elongated Thalestris. 



joints ; 



middle | not much f f aliaceous Dactylopus. 



joint { longer than | 



of the I the first joint ;{ elon ated, sub- 

 outer fifth pair of | falciform, and 



-S 

 CO 



both 

 branches 



com- 

 posed of 



[_branch [_ feet (^ strongly spined Peltidium. 



the outer f one joint ; C two-branched Westwoodia. 



branch | mandible- < 



composed of 1 palp (. simple, bisetose Ilyopsyllus. 



three, the 

 inner of ^two-joints Zaus. 



Genus 24. DACTYLOPUS, Glaus (1863). 



Body elongated, more or less cylindrical; first pair 

 of antennae usually 5 9-jointed ; in the male genicu- 

 lated ; inner branch of the second pair of moderate size, 

 2- or 3-jointed. Maxilla-palp well developed, the 

 basal portion numerously clawed and having one or 

 two lateral processes ; mandibles well developed, the 



