160 Anyials Entomological Society of America [Vol. X, 



slender; hairs on joints one and two irregular, on joints three to eight 

 distributed in a fringe on widest anterior part of segment; on tcmiinal 

 joint hairs and spines; hairs increasing in length towards apex of antenna; 

 on joint two a group of six pores (PI. XV, fig. 10). Legs stout and short; 

 tibia more than twice as long as tarsus; trochanter with two long hairs 

 and a group of pores varying in number; hairs on all parts, niost numer- 

 ous on tibia; digitules on tarsus and on claw fine unknobbed hairs 

 (PI. XV, fig. 17). Rostrum wanting. Anal tube represented by an 

 infolding of the body wall and not strongly chitinised. Two pairs 

 of spiracles on thorax and eight pairs on abdomen; the former incon- 

 spicuous, the latter with well developed stiginatal tubes with' two 

 rows of pores in constriction. Integument covered with hairs, becoming 

 more numerous posteriorly; pores of two types (PL XV, fig. IS) densely 

 scattered over cephalic region and less densely over thorax and abdomen ; 

 smaller type of pore predominating. 



Male, second stage. — Not found. 



Male, third stage. — Similar to stage three of female; pores less numer- 

 ous than in stage three of female; six posterior abdominal segments 

 strongly chitinised. 



The fourth, fifth and six stages of the male of this species have not 

 yet been found. 



This study has been made in the Entomological Laboratory 

 of Stanford University, and there, are preserved the type 

 specimens of Xylococcus alni n. sp. 



The drawings on Plate XIII and figures three and six on 

 Plate XIV are the work of Mr. W. S. Atkinson. The other 

 drawings were made with a camera lucida, and an oil immersion 

 was used in studying the structure of the wax pores. 



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