THE CANADIAN ENTOMOLOGIST 



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chitinized area surrounding the base of the anal tube, everywhere beset with 

 small, spike-like spines. Legs lacking. Antennae reduced to mere chitinized 

 points. Anal tube of a very distinctive type (Fig. 17A), its inner end terminating 

 in a series of tentacle-like processes (in my single specimen 7 in number ^ these 

 processes and the tube itself thickly beset with pores. Dermal pores of three 

 types. Of these, one (Fig. 17B) is more or less 8-shaped, with one of the loculi 



Fig. 17. — Stigmacoccus asper Henipel. A, anal tube, with chitinized area and spiracles at its base; B, 8-shaped 

 pore; C, simple pore, from clusters about spiracles; D, spiracle, external opening at lower end. 



much smaller than the other. Another resembles the first in shape, but is much 

 smaller and is borne at the inner end of a short duct. The third (Fig. 17C) 

 appears as a simple ring with the enclosed area partially chitinized. The pores 

 of the last type form clusters about the spiracles; those of the first two types 

 are scattered about over the body. Eight pairs of abdominal spiracles present, 

 all of the type indicated in Fig. 17D. The last abdominal pair are situated 

 at the edge of the circular, chitinized area w^hich surrounds the base of the 

 anal tube. 



Material examined. Part of the type material, this including a single 

 immature individual. 



Genus Xylococcus Loew. 



1903. Fernald, Cat. Coccidae, p. 32. 



1917. Florence, Ann. Ent. Soc. Am., vol. 10, p. 147. 



This genus has been assigned by previous authors to the subfamily 

 Margarodinae because of the supposed absence of mouth-parts in the adult female. 

 I have at hand a series of adult females of X. macrocarpa Coleman, and in this 

 series practically every stage from a complete absence of mouth-parts to mouth- 

 perts which are to all appearances functional is represented. It appears from 

 this series that the foundations of the mouth-parts are probably always present, 

 but that in some instances they do not become chitinized. 



I have not observed mouth-parts in the adult females of other species of 

 Xylococcus, but the number of specimens examined is small, and it is not at all 

 improbable that the examination of a long series would reveal conditions similar 

 to tho.se found in A', macrocarpce. 



It is becoming increasingly evident that the distinction heretofore drawn 



