42* A CONTRIBUTION TO THE KNOWLEDGE OF 



The specimens from A triplex near Bar stow and Eurotia near Atolia, 

 Cal., are scarcely more than 2 mm. high and are of a uniform dark brown 

 color except for the apex, which is black. The secretion appears to be 

 very thin. 



The specimens from Atriplex near Lone Pine, Cal., are slightly larger 

 than the preceding, are very irregular in form and have the groundcolor 

 white, with brown or black markings about the base and at the apex. 



The specimens from Atriplex confertifolia at Lancaster, Cal., are 

 of about the form and shape of the New Mexico specimens, but are con- 

 siderably smaller and vary from gray to brown in color. 



Morphological characteristics. As far as may be determined from 

 the material at hand all the above lots of specimens agree morpholog- 

 ically. The description is drawn from specimens from Las Cruces, 

 N. Mex., which agree in all respects with specimens from the same local- 

 ity determined by Professor Cockerell as this species. 



At maturity the insect is very convex and the derm is heavily chitin- 

 ized throughout. The anal plates are borne at the apex of a low pro- 

 jection. Posterior pair of stigmatic depressions entirely lacking, their 

 presence not indicated in any manner. Anterior stigmatic depressions 

 (Fig. 19B) shallow, beset with many short, tubercle-like spines, of which 

 three are somewhat larger than the others. Extending from each de- 

 pression to the corresponding spiracle is a broad belt of pores. Mar- 

 ginal spines lacking. Anal plates (Fig. 19D) borne at the apex of a 

 low prominence, more or less circular in outline, each with three apical 

 setae, a single subapical seta and three very small fringe setae on each 

 side. (The statement as to the setae of the anal plates is very liable to 

 error, due to the heavy chitinization of this region.) Derm, before be- 

 coming chitinized, with large numbers of small pores with heavily chi- 

 tinized rims. Antennae (Fig. 19A) quite long and slender, seven-seg- 

 mented. Legs large; tarsus at base nearly as wide as the tibia, slightly 

 curved (Fig. 19C) ; digitules of the claw slender, but little expanded at 

 the tip. 



Notes: Although all the material examined appears to agree as far as mor- 

 phological characters are concerned there is a very wide divergence in habit, as is 

 indicated above. Whether we are dealing with at least three distinct species or 

 whether these are all forms of a single species can only be determined by an ex- 

 amination of a much larger series of collections. 



