422 



BUREAU OF ANIMAL INDUSTRY. 



side contiguous, as broad as long; cox?e I triangular, apex n^ay be prolonged ante- 

 riorly beyond the corresponding anterior point of dorsal shield, reaching anterior 



angle of base of capitulum, or may 

 be very short, base posterior and 

 more or less distinctly bidentate, 

 the teeth short, often slightly pro- 

 nounced, or quite prominent, the 

 lateral tooth in some cases pro- 

 longed into a well-marked spine. 

 Tarsi like those of female. 



Female. — Body elliptical, as 

 broad in front as in back, usually 

 somewhat constricted in middle, 

 near IV pair of legs; may attain 

 13 mm. long, 7.5 mm. broad. 

 Color exceedingly variable; live 

 specimens vary from a tawny yel- 

 low (younger forms) to an olive 

 green (very old specimens), alco- 

 hol specimens from yellow to red 

 or black; the excretory system 

 often shows through the cuticle 

 as tortuous whitish canals. Dorsal 

 shield (scutum) very small, visible 

 as a dark brownish spot in a de- 

 pression at anterior end of median 

 line; usually about 1.1 mm. long 

 by 0.8 to 0.9 mm. broad, decidedly 

 emarginate anteriorly to receive 

 capitulum; lateral borders nearly 

 straight and paral- 

 lel in anterior por- 

 tion, from antero-lateral points to eyes, then convergent from eyes 

 caudad, forming a more or less bluntly rounded posterior angle in 

 median line; cervical grooves divide the anterior half of scutum into 

 three more or less equal longitudinal fields, and diverge posteriorly; 

 surface of scutum provided with short bristles which are more numer- 

 ous near anterior border and near the eyes than elsewhere. Eyes 

 rather small near anterior third of margin of scutum. On nearly the 

 entire length of dorsal surface of body are two 

 antero-posterior grooves, interrupted or nearly 

 effaced near plane of IV pair of legs, and ending a short dis- 

 tance from the shield and from posterior margins of body; 

 also an unpaired median groove in posterior half of body ; 

 all three vary with the muscular contractions and may more 

 or less completely disappear when body is replete. Ventral 

 surface shows four pairs of more or less distinct marginal 

 constrictions corresponding to the four pairs of legs, the IV 

 constriction being most marked; antero-median region also 

 depressed at insertion of capitulum; vulva small, median, 

 at plane of coxse I; sexual grooves corresponding to the paired 

 dorsal grooves; but showing some variation in different 

 specimens; median groove extending from anus to posterior margin. Anus about on 

 border of second and last thirds of body. Stigmata short oval; stigmal pore slightly 



Fig. 142. — Ventral view of same specimen. In the living 

 animal, a distinct peristalsis can be seen in the dark 

 canals which shine through the integument. Original. 



Fig. 143.— Stig- 

 mal plate of 

 male. Great- 

 ly enlarged. 

 Original. 



Fig. 144. — Stigmal plate 

 of female. Greatly en- 

 larged. Original. 



