1917] Pacific Coast Species of Xylococciis 153 



on the eighth abdominal segment ventrally; dorsally two pairs on the 

 last two abdominal segments; a single pore adjacent to each abdominal 

 spiracle; in lateral view pores are short chitinous tubes (PL XIV, 

 figs. 4a and 4b). 



Female, second, third and fourth stages. — Length from about 1.50 mm. 

 to about 4 mm., breadth from about .75 mm. to about 2 mm. Color 

 dark red, posterior end of body brown owing to chitinous nature of last 

 abdominal segments. Shape oblong-oval, bluntly rounded anteriorly; 

 abdominal segments well marked, posterior segments being more 

 compressed than in stage one. Eyes represented by small black 

 pigment spots (disappearing on boiling in KOH), situated near but 

 not contiguous to antennal discs. Antennse represented by microscopic 

 chitinous discs bearing a few hairs varying in length and number. Legs 

 wanting. Rostrum large, situated about middle of body. Anal tube 

 in second stage with an increased number of spinnerets opening into it 

 anteriorly, in third stage with two anterior circles of spinnerets, and in 

 fourth stage with three anterior circles of spinnerets (PI. XIV, fig. 5). 

 Two pairs of thoracic and eight pairs of abdominal spiracles; the former 

 inconspicuous, the latter with well developed stigmatal tubes differing 

 from those of first stage as illustrated (PI. XIV, figs. 3 and 6) , and increas- 

 ing in length in the successive instars ; one row of pores in constriction in 

 second and third and two rows in fourth stage. Integument smooth 

 and shining, bearing a few microscopic hairs, and a few lateral abdominal 

 spines. Pores of two types, (PI. XIV, fig. 7), compound type pre- 

 dominating, distributed irregularly on cephalic and lateral areas and 

 arranged in transverse rows on segments two to seven of abdomen, 

 simple type of pore interspersed among compound type. In successive 

 stages hairs and spines increase in size and pores in number. Pores 

 much more numerous in fourth than in preceding stages, arranged 

 in bands on abdomen, and in all stages increasing in number posteriorly. 



Female, fifth stage, adult. — The adult varies in length from 6 mm. to 

 3 mm. and in breadth from 3 mm. to 1.50 mm.; measurements of largest 

 and smallest specimens found when moulting were respectively 5 mm. 

 X 2.50 mm. and 3 mm. x 1.50 mm., specimens found with eggs 6 mm. 

 X 3 mm. and 4 mm. x 2 mm. Color when living dark olive brown, 

 with an indistinctly spotted appearance due to dark particles in the 

 body fluid; on ventral surface revolute edges yellow; antennae and legs 

 yellow. Shape oblong-oval, broadest in thoracic region; segments all 

 well defined. Eyes small, black, situated laterad to antennae. Antennae 

 stout, nine-jointed; formula 1, 3, 2, (4, 8, 9), 5, (G, 7); joint one longest 

 and stoutest; joint three longer and more slender than two (division 

 between joints two and three not always clearly defined); joints four, 

 five, eight, and nine sub-equal in length and diameter; segments four 

 to eight widening anteriorly where they bear a fringe of hairs; hairs 

 increasing in length towards apex of antenna; last joint flattened at 

 apex, longer at outer side, bearing a few spines as well as hairs; on joint 

 two a small group of pores varying in number, sometimes absent 

 (PI. XIV, fig. 8). Legs stout and rather short; tibia twice as long as 

 tarsus; trochanter bearing two long hairs and a group of pores varying 



