SUBFAMILY XYLOCOCCINAE 81 



nymphal stage and wanting or greatly reduced in size and inconspicuous 

 in the second, third, and fourth; and when present are similar in form. 

 The profemora are never greatly enlarged and the prothoracic legs are 

 never fitted for digging. The body is never provided with an anal cleft 

 and opercula, an anal ring and anal ring setae, anal lobes and anal setae, 

 octacerores, pilacerores, or ceratubae. The caudal end of the rectum is 

 strongly chitinized and provided with one or more rings of anacerores 

 excreting a long glassy tube of wax. The caudal abdominal segment is 

 short, narrow, and projects beyond the other segments; the segments are 

 not campanulate. 



The male has large coarsely facetted compound eyes and are not 

 provided with ocelli. The abdomen is not provided with long lateral 

 filaments, but bears tufts of long filaments of wax. The stylus is short 

 and conical. 



The typical genus, Xylococcus, of the subfamily Xyloeoccinae 

 was based upon the species filiferous Loew, described in 1882 as 

 infesting Tilia europaea and T. grandifolia in Austria. Four 

 species have been described from North America, betulae Pergande 

 from birch and poplar from the Lake Superior region, and three 

 species from California, quercus Ehrhorn from live oak, macrocar- 

 pae Coleman from the Monterey cypress, and alni Florence from 

 alder. Two species have been described from Japan by Kuwana, 

 napiformis from oak and matsumurae. The first species has been 

 made the type of a new genus, Matsucoccus by Cockerel!. It has been 

 placed in the subfamily Kuwaniinae. The second species, judging 

 from the figures and descriptions of the species, the presence of 

 mouth-parts in the adult female, and the presence of anal setae and 

 apparently anal ring setae in the first nymphal stage, has no 

 relation with the genus Xylococcus as here defined and probably 

 belongs to the Eriococeinae. 



The most complete account of the life history of any of the 

 species of Xylococcus is that given by H. G. Hubbard and Th. 

 Pergande of the birch xylococcid. The account of Florence based 

 upon the study of the three species found upon the Pacific Coast 

 confirms for the most part and amplifies the excellent account of 

 these observers. The following descriptions are based upon the 

 work of these writers. 



The adult female is ordinarily buried in a cavity in the bark. 

 The eggs are deposited in a depression formed by the collapse of 

 the ventral portion of the abdomen of the female and the sides of 

 the opening in the bark. 



The young nymphs, when they emerge from the egg, seek a 

 place like other coccids of the first nymphal stage, where they can 



