THE COCCIDAE OF SOUTHWESTERN UNITED STATES 21 



like a deposit of alkali on the soil, the surface more or less visible be- 

 tween ; short, thick, irregular marginal tufts" : according to the original 

 description. 



r '.'.,.' 



f- i 



Fig. (t.Phenacoccus betheli Ckll. : anal lobes and penultimate cerarius, left dorsal, 

 right ventral. 



Morphological characteristics. The number of pairs of cerarii is 

 difficult to determine because of the distortion arising from the un- 

 uisual convexity of the insect and the resemblance of the cerarian spines 

 to those of the dorsum. Whether or not the eighteen pairs character- 

 istic of this genus are present could only be determined by an examina- 

 tion of specimens taken before this convexity has been attained. Count- 

 ing forward from the anal lobes I have been able to detect but six distinct 

 pairs. Anal lobe and penultimate pairs with six to ten spines, third pair 

 with two spines close together and several others scattered about, remain- 

 der with but two. In all the cerarii the spines are somewhat constricted 

 at the base, giving them a "spearhead-shaped" appearance, those of the 

 anal lobe pair largest, the others becoming successively smaller. All of 

 the cerarii with but few pores and without auxiliary setae. Anal lobes 

 with more or less irregular chitinization both dorsally and ventrally and 

 with numerous long, slender setae on the ventral side. Spines of the 

 dorsum of the body shaped like the cerarian spines and as large as the 

 smaller of the latter, few, scattered. Tubular ducts all small and without 

 a raised rim about the mouth. Anal ring setae considerably longer than 

 the diameter of the anal ring and scarcely half as long as the anal lobe 

 setae. Antennae eight to nine-segmented. Legs rather short, the claw 

 with a distinct tooth. 



Notes: The numerous spines of the last three pairs of cerarii and the long 

 slender setae of the ventral side of the anal lobes are very distinctive features of 

 this species. 



