A CONTRIBUTION TO THE KNOWLEDGE OF 



Morphological characteristics. Derm of the dorsum membranous, 

 that of the venter more or less chitinized. In shrinking during the course 

 of oviposition the body seems to fold but once, this fold occurring along 

 a transverse line just in front of the middle pair of legs, the posterior 

 portion of the body turning up at right angles to the anterior portion. 

 Stigmatic depressions obsolete, their position indicated merely by a nar- 

 row belt of pores marking each stigmatic furrow. Marginal spines 

 (Fig. 20D) small, sharply pointed, swollen at the base, arranged in a 

 single, definite row. Anal plates (Fig. 20C) rather irregular in form, 

 each with two stout spines and three slender setae and with two small 

 fringe setae on each side. Antennae (Fig. 20A) seven-segmented, 

 rather stout. Legs well developed; digitules of the claw not greatly ex- 

 panded at the tip. 



First stage larva without differentiated stigmatic spines; marginal 

 spines of same type as in adult; antennae rather stout, the third joint 

 unusually long (Fig. 20B). 



Notes: The only other species of this genus available for comparison is 

 C. cajani (Maskell). The two differ very markedly, especially in the fact that 

 C. cajani possesses a single very long spine at each stigmatic cleft. 



Genus TOUMEYELLA Ckll. 



Toumeyella mirabilis Ckll. 



Fig. 21. 



Type host and locality. From Prosopis velutina (= P. juliflora var. 

 glandulosa of Ckll.), Tucson, Ariz. 



Material examined. From type host and locality. 



Habit. A large species, 5 to 8 mm. long, rather high convex, roughly 

 circular in outline but usually more or less irregular from crowding on 

 the twigs. Groundcolor brown, but the dorsum with more or less irreg- 

 ular rows of white areas (the "conspicuous irregular rings of snow- 

 white, waxy secretion" of Cockerell), each of which surrounds a central 

 depression in which the derm is nearly black. 



Morphological characteristics. Derm at maturity becoming quite 

 heavily chitinized and deeply pigmented. The description here given is 

 based upon specimens taken before this chitinization of the derm had 

 progressed so far as to render study too difficult. Stigmatic depressions 

 shallow or nearly obsolete, connected with the corresponding spiracles 

 by a broad belt of pores. Stigmatic spines practically of same size and 

 shape as the marginal spines (Fig. 21C), noticeable only because of 

 their grouped position. Anal cleft of ordinary depth, the edges not 



