DISCUSSION OF GENERA AND SPECIES 33 



on dry hillsides. The insects are ordinarily found at the bases of the 

 stems. Parrott has recorded the species from Kansas, but has noted 

 certain differences between the specimens from the two regions. It is 

 quite possible that he was dealing with a different form. 



The general appearance of the adult female has been well described 

 by Ehrhorn and Parrott, but there remain certain important details of 

 structure that have been overlooked. 



In the adult female the posterior end of the body (Fig. 13) is 

 heavily chitinized, although this area is not definitely delimited as hi 

 A. ariditatis Ferris, the margin is crenulate and both dorsum and venter 

 show numerous shallow furrows. The margins of this chitinized portion 

 are beset with small, slender spines. Beginning at the anterior margin of 

 this area is an irregularly single or double row of short, stout, acorn- 

 shaped spines (Fig. 13C), that extends entirely around the anterior por- 

 tion of the body. These spines are of various sizes, but all are of the 

 same characteristic shape, broad and short, very slightly or not at all 

 constricted at the base and with the apex produced into a sharp point. 

 Just within this series of spines lies a zone of rather conspicuous, multiloc- 

 ular pores (Fig. 13Z)), this zone disappearing on the head and widening 

 opposite the spiracles. Within this zone are a few slender spines, and 

 distributed irregularly over the body are a few tubular ducts of the type 

 shown in Fig. 13B. 



The anal plate (Fig. 13 A) is not emarginate at the tip. It bears sev- 

 eral setae. The anal ring lies immediately beneath this plate (not anteri- 

 orly to it as in some species). The edges of the ventral furrow, which 

 is continuous with the anal cleft, are contiguous and heavily chitinized. 



Aclerda tokionis Ckll. 

 Fig. 14. 



This is an introduced species, probably a native of Japan, which has 

 once been taken from bamboo on the Stanford campus. Specimens from 

 this material agree entirely with specimens from Japan. 



This species differs in certain conspicuous details from the preced- 

 ing. The marginal spines (Fig. 145) are smaller and quite differently 

 shaped, being blunt-tipped and definitely constricted toward the base. 

 The marginal series of these spines extends almost to the margins of the 

 anal cleft. The zone of multilocular pores seen in A. calif arnica is lack- 

 ing, being replaced by a similarly situated zone of small, straight tubular 

 ducts which are mingled with a few large ducts of the type shown in 

 Fig. 135 and a few small spines. The anal plate (Fig. 14C) is distinctly 



