252 U.S. NATIONAL MUSEUM BULLETIN 261 



scutellum usually weakly transversely striate; otherwise as in Phera. 

 Forewing coriaceous, with an apical membrane, usually not punctate, 

 claval veins not fused, otherwise as in Phera. Hindwing with vein R^-s 

 almost always incomplete, otherwise as in Phera. Anterior tibiae not 

 dilated apically. Hindlegs with femoral setal formula 2:0:0; first 

 tarsomere with length equal to combined length of second and third 

 tarsomeres. 



Male genitalia: Pygofer not strongly produced, broadly rounded 

 posteriorly, with numerous evenly dispersed microsetae over most of 

 disc, with a vestigial process on ventral margin. Plates not fused basally, 

 not extending as far posteriorly as pygofer apex, each triangular, with 

 numerous evenly dispersed microsetae. Style short, not extending much 

 farther posteriorly than apex of connective, with a preapical lobe. 

 Connective quite broad, not Y- or V-shaped, with a short median keel. 

 Aedeagus symmetrical, shaft nearly always curved dorsally and an- 

 teriorly in apical half, with two pairs of ventral basal processes which 

 are variable interspecifically. Paraphyses absent. 



Female abdominal sternum VII with posterior margin broadly, 

 regularly, and shallowly concave. 



Species of Cuerna have been studied from the area from Alaska to 

 Honduras and from the eastern to the western coast of the United 

 States. Cuerna is very closely related to Oncometopia and Tapajosa, from 

 both of which it may be separated easily by the keeled ventral edge of 

 the proepimeron, which does not occur in either of the other genera, 

 and by the concealed posterior meron when the wings are at rest. 

 It is also noteworthy that in Cuerna the aedeagal shaft is almost always 

 curved cephalad, a character very rare in Oncometopia. 



The genus Cuerna was revised by Dr. M. W. Nielson (1965a) during 

 the progress of the present work. Nielson studied the concealed char- 

 acters at the base of the ovipositor and found them of at least equal 

 value to the characters of the male genitalia for species differentiation. 

 He recognized 22 valid species. Cuerna costalis (Fabricius) is a known 

 vector of Phony Peach Disease and it and two other species are among 

 a number of leafhoppers which are capable of transmitting Pierce's 

 disease of grapes. Nielson's account of the known host plants of some 

 of the species included alfalfa, beets, corn, cranberry, grass, lespedeza, 

 peach, strawberry, wheat, and willow. 



Turner and Pollard (1959a) published much information concerning 

 the life history and behavior of C costalis (Fabricius), including a color 

 description of nymphs and adults, some measurements of the nymphal 

 instars, overwintering habits, food plants, mating and oviposition, 

 flight characteristics and parasites. This species oviposited in the field on 

 peach, cowpea, and four species of grasses. 



