438 Pomona College Journal of Entomology 



is the most apparent difference between the species and its variety. The 

 species is brownish red to orange, usually quite light colored, whereas the 

 varietal form is very dark reddish brown. The principal structural differences 

 are thoracic ; the dorsulum in the variety is distinctly less arched than in the 

 species, and the notum is finely pubescent ; the notum of the species is also 

 pubescent but much less conspicuously. 



These two forms were separated as species in the provisional synopsis chiefly 

 on the difference in the trend of the facial cones, but this is not a sufficiently 

 constant character to warrant this separation. 



The form mentioned in the provisional synopsis as Trioza sulcata siiiiilis 

 is found on further study to be identical with T. frontalis. Therefore the 

 varietal name becomes synonymical. 



Trioza similis fovealis (Crawf.) 



(Syn. Trioza fovealis Crawford) 



(Fig. 152, H; 154, I) 



This varietal form is very similar to the species in almost all characters. The 

 following differences make it evident that it is truly a variety. The facial cones 

 are distinctly shorter and less slender in the varietal form ; the epimeron is not 

 so prominent as in the species ; the tergites of the abdomen are concolorous 

 with the sternites ; this character is of more importance than it might at first 

 thought seem, since the relative coloration of the abdomen dorsad and ventrad 

 is quite constant. The female genitalia are quite similar, though not exactly so. 

 Described from one female taken in Colorado by C. F. Baker. 



It will be noted in Fig. M, on page 348, Vol. II, No. 4 of the Pomona 

 Journal, that the frons and the insertion of the antennje is erroneously repre- 

 sented. The illustration presented for the varietal form is more correct for 

 the species, also. 



Trioza albifrons Crawf. 

 (Fig. 154. L) 



Pomona Journal Ent. Vol. II, No. 4, page 355. The type locality of the 

 species is Claremont, California. Subsequent to the description of the species 

 numerous specimens of both sexes were collected at Nordhoff, California, by 

 D. L. Crawfora, on leaves of nettle (Urtica holosericea). Since only the 

 male was known from the Claremont forms, the characters of the lemale 

 are here added. 



Female. — .Abdomen large, stout. Genital segment long, almost three times 

 as long as preceding ventral sclerite ; dorsal plate very slightly longer and 

 less acute than ventral plate ; genital pore less than one-third the length of 

 dorsal plate. Pubescence sparse. 



Trioza assimilis Crawf. 

 (Fig. 152, G : 153, I ; 154. H ; 155, G) 

 Length of body 2.3 mm.; length of forewing ?>.2i mm.; greatest width 1.4 

 mm. ; width of vertex between eyes .47 mm. ; with eves .70 mm. General 



