DASCYLLIDAE. 181 



Tribe III.— HELODINI. 



Sometimes elongate, usually oval species, of varied color, covered 

 with a very deciduous pubescence ; the clypeal suture is not visi- 

 ble ; the last joint of the labial palpi is frequently inserted at the 

 side of the preceding joint and not at the apex as in other insects. 

 The thorax is usually very small ; the presternum in front of the 

 coxae is very short, and not visible between them. The anterior 

 coxaa are long, oblique, and conical, and lap over a portion of the 

 middle coxse ; the hind coxal plates are strongly dilated inter- 

 nally. Tibiae sulcate externally, usually with small spurs, in 

 Scyrtes with longer ones. Tarsi with the fourth joint larger than 

 the third, bilobed ; claws simple. The antennae of the male of 

 Prionocyphon discoidea have the joints 4 — 10 furnished on each 

 size with a cylindrical appendage longer than the joint. The fifth 

 ventral segment is rounded at tip. 



Our genera, all having the fifth joint of the tarsi short, are : — 



Labial palpi with the third joint inserted on the side of the second ; 



Hind legs large, saltatorial. Scyrtes. 



Hind legs moderate; 



First joint of antennae much dilated. Pkionocyphon. 



First joint of antenna? moderate. Helodes. 



Labial palpi with the third joint at the end of the second. Cyphon. 



In Helodes the hind coxae are suddenly dilated internally, and 

 in our species, the head is covered by the thorax, which is rounded 

 in front; these species form Sacodes Lee, which must be sup- 

 pressed. In Prionocyphon and Cyphon the hind coxae are strongly 

 but gradually dilated internally. Scyrtes and Cyphon occur on 

 both sides of the continent ; the other two genera, thus far only 

 on the Atlantic slope. 



Tribe IV.— EUCOfETIlVI. 



Eucinetus, a genus of wide distribution, composes this tribe ; 

 the mouth is prolonged ; the head deflexed, without distinct 

 elypeal suture ; the prosternum is exceedingly short in front of 

 the coxae, which are long and conical ; the middle coxae are large 

 and flat ; the posterior ones are dilated into immense oblique 

 plates, concealing the hind legs in repose ; the metasternum is 

 consequently short, and rhomboidal; the tibial spurs are distinct, 

 the tarsi somewhat elongated, filiform, joints 1 — 4 decreasing in 



