DASCYLLIDAE. 119 



Tribe II.— DASCYLL.INI. 



The clypeal suture is sometimes visible, and sometimes behind 

 the labrum may be seen a membranous epistoma. The prester- 

 num does not articulate with the mesosternum; the plates of the 

 hind coxae are gradually dilated internally ; the onychium is small, 

 bisetose, and sometimes wanting. Our genera are : — 



Tarsi not lobed beneath ; 



Claws simple ; antennae strongly serrate. Stenocolus. 



Claws simple ; antennae nearly filiform. Anchytarsus. 



Claws serrate ; antennas nearly filiform. Odoktonyx. 

 Tarsi with membranous lobes beneath ; 



Tarsi dilated ; first joint not elongated. Dascyllus. 



Tarsi slender ; first joint longer. Anorus. 



Stenocolus and Anorus are found only in California ; Dascyllus 

 on both sides of the continent ; Anchytarsus and Odontonyx in 

 the Atlantic States ; Stenocolus is remarkable for the middle coxae 

 havinsr a large trochantin. 



Sub-Family II.— HELODIDAE. 



This sub-family contains a number of small species found on 

 plants in moist situations, and readily recognized by the anterior 

 and middle coxae having no trochantin. They are divided into 

 four tribes, the first of which resembles in many points the tribe 

 Chelonariini of Byrrhidae, while the second recalls the sub-family 

 l'sephenidae of the Parnidae. 



Tarsi with fourth joint very small, third lobed beneath. Ptilodactylisi. 



Tarsi with fourth joint not smaller than the third ; 



Posterior coxee moderate ; 



Prostermim distinct before and between the coxae. Eubriini. 



Presternum very short before the coxae. Helodini. 



Posterior coxse very large. Euclnetini. 



Tribe I.-PTII,OI>ACTYI.I]VI. 



Represented in the Atlantic district by three species of Ptilo- 

 dactyla ; they are oval, brown, finely pubescent insects of convex 

 form ; the antennae of the males have arising from the base of the 

 joints 4 — 10 a slender cylindrical appendage, equal in length to the 

 joint itself; the clypeal suture is very distinct, and the front rises 



