AMERICAN PSYLLIDAE II 361 



ventral segment short, produced apically into a short and acute point. Male. — 

 Abdomen slender, arched dorsally, broadest across third dorsal segmental 

 plate, the anal dorsal plate scarcely visible above ventral segmental plate. 

 Genital segment about as long as two preceding, somewhat refle.xed, with 

 apical margin horizontal ; claspers rather short, simple, slender and acute in 

 distal half, arcuate and briefly pubescent. Anal projection bilobate when 

 viewed laterally ; the longest lobe horizontal and at right angles to the other, 

 reaching fully to base of claspers ; pubescence short, whitish. 



Described from numerous females and several males taken in Ormsby 

 County, Nevada, and Santa Clara County, California, by C. F. Baker. 



This species is more or less variable in some respects and it is therefore, 

 quite difficult to determine the line of separation between this and closely 

 related species. Wherever a large number of specimens belonging to some 

 common species is studied this difficulty of gradual variation is nearly al- 

 ways encountered. It is quite possible that these variations are slowly giving 

 rise to new species, but while the variations are slight and grade into each 

 other the only course possible is to class the entire group of slightly varying 

 forms into one species. In this specific group the genital characters are the 

 most constant and reliable for diagnosis. 



Trioza varians a. sp. 



(Figs. 128 V; 129 O; 130 U, V.) 



Length of body, 2.1 mm.; length of forewing 3.3 mm.; greatest width of 

 wing, 1.4 mm.; width of vertex between eyes, .41 mm.; with eyes, .70 mm. 

 General color, dark brown to black with conspicuous stripes and bands of 

 yellowish white ; frontal plates bordered with light band ; whitish band on 

 pedicle of eye ; on posterior margin of dorsulum and several stripes on dorsal 

 surface of scutum and dorsulum ; upper margin of ventral abdominal plates 

 whitish. 



Head somewhat deflexed, finely punctate. Posterior margin of vertex 

 narrowly and sharply elevated into a ridge over three-fifths of the line between 

 posterior ocelli ; discal area with a sulcus extending parallel with median 

 suture ; margin of frontal plates elevated arcuately ; when viewed from side 

 raised plate-like ; deeply emarginate anteriorly. Anterior ocellus not visible 

 from above. Facial cones medium in length, divergent, subacute, subvertical 

 and not visible from above, slightly rugulose, sparsely pubescent. Antennne 

 inserted below frontal plates, in front. 



Thorax strongly arched, finely punctate. Pronotum short, depressed 

 below dorsulum and head ; with a fova: on each side above pleurites ; lighter 

 in color than dorsulum. Dorsulum quite strongly ascending, roundly pointed 

 anteriorly ; with a stripe of lighter brown on dorsal surface. Wings hyaline, 

 about two and a half times as long as broad, broadest across middle of first 

 marginal cell, quite broadly rounded apically ; radius as long as second cubital ; 

 first marginal cell smaller than second. 



Female. — Abdomen arched dorsally ; borders of ventral segmental plates 

 lighter colored. Genital segment about as long as anal segment ; concolorous 



