18 BULLETIN 85, UNITED STATES NATIONAL MUSEUM. 



formerly of Pomona College, I owe much gratitude for first starting 

 me on this task and helping me through many difficulties, as well as 

 placing before me his extensive collections. Without Dr. L. O. 

 Howard's kindness in loaning to me for study the large collection of 

 Psyllidse from the United States National Museum, this work would 

 have been much more hmited in its scope. To many others, also, I 

 desire to express my thanks for assistance rendered in one form or 

 another; Prof. J. H. Comstock; Mr. E. A. Schwarz, of the United 

 States National Museum; Miss Edith M. Patch, for the loan of para- 

 types of her species; Dr. L. Melichar, and Dr. O. M. Renter; Mr. 

 E. P. Van Duzee, and Prof. T. D. A. Cockerell. 



EXPLANATION OF DESCRIPTIONS. 



Since the two sexes differ very little in this family, except in the 

 genitaUa, one description is given for both the male and female of 

 each species, followed by a description of the genitaha first of the 

 male, then of the female. If any other secondary differences between 

 the sexes do occur, these are noted in the general description. 



SYSTEMATIC TREATMENT. 



SYNOPSIS OF THE SUBFAMILIES. 



a}. Head deeply cleft in front, with the antennae attached to the truncate anterior 

 ends on each side of cleft (see fig. 122); gense seldom produced into conical 

 processes; furcation of media not dichotomous (see figs. 395 and 492) ; hind tibiae 



often with a spur at base Carsidarin^. 



a^. Head not as above (head may appear to be cleft, but this is due to the genal cones, 



and the antennae are not attached to the ends of these). 



b^. Frons not covered by genae; genae not produced into conical processes (except 



in Calophya) ; front ocellus at extremity of frons. 



c^ Vertex flat and horizontal, with frons beneath it in the form of a narrow 



(usually elongate) sclerite from clypeus to front ocellus; wings often more 



or less thickened and maculated Livhn^. 



c^. Vertex rounded downward in front, not horizontal, with frons as a distinct 

 eclerite usually forming a uniformly smooth surface with vertex and genae; 



wings usually membranous Pauropsyllin^. 



£2. Frons covered by genae; genae usually produced into conical processes (genal 

 cones) ; front ocellus imbedded between vertex and genae. 

 c^ Forewing with more than the usual two marginal cells, the additional ones 

 (or one) being formed by the branching of the radial sector or a cross vein 



from same to media Ceriacremin^. 



(P. Forewing with only the usual two marginal cells, formed by furcation of 



media and cubitus; radial sector not branched and without cross vein to 



media. 



d^. Basal tarsal segment of hind legs without a pair of black, claw-like spines 



at tip; radius, media and cubitus usually diverging at same point from 



basal vein; wings usually angulate at apex Triozin^. 



d^. Basal tarsal segment of hind legs with two black, claw-like spines at tip; 

 the three veins not diverging at same point from basal vein, but media 

 and cubitus with a common stem (cubital petiole); wings rarely angulate 

 at apex PsYLLiNiE. 



