7i8 



ARTHROPODA 



Genital pore surrounded by hairs. Anal ring nearly circular. 

 Stigmal plates with prominent dorso-lateral prolongation, aperture 

 and chamber large and elongate, goblets of medium size. Postero- 

 lateral projections of plate small. Capitulum with short postero- 

 lateral projections of base. External article with large recurved 

 tooth, a smaller subapical, and a very small apical tooth. Hypo- 

 stome with three rows of strong denticles. Palpi with lateral margin 

 convex; first article with four or five bristles; third article rather 

 triangular dorsally. Legs: outer spur of coxa I. longer than inner 

 spur; trbchanter I. with retrograde curved blade. 



Male. — Length, 4 by 2 -5 millimetres broad. Body oval. Scutum 

 covers dorsum except capitulum; deep reddish-brown, marked by 



hairs. Genital grooves running parallel caudad. 



Young Female. — This is the form most commonly found. Length, 

 4*5 to 7 millimxctres. Breadth, 2-3 to 2-6 millimetres. Body oval. 

 Scutum covers about 0-43 of the length of the body. Eyes not 

 very distinct. Vulva between coxae IL 



Replete Female.— Length about 16 millimetres, and 6 millimetres 

 to 9*5 milhmetres thick. ' Eyes more distinct than in young female. 

 Vulva may shift to level of first and second intercoxal space, 

 and a radial groove may appear on each side between the anal 

 and the genital grooves. Coxae naturally farther apart than in 

 young female owing to repletion. 



Hexapode Larva,—o -6^6 millimetre in length by 0-316 millimetre 

 in breadth, with the caudal end broader than anterior end. 



four elongate 

 spots arranged in 

 semicircle; two 

 elongated r e n i- 

 f or m spots behind 

 these, one elon- 

 gated median spot, 

 and two shorter 

 elongate subme- 

 dian spots, and an 

 indistinct forked 

 spot. 



Fig. 328. — Dermacentor salmoni Stiles, 1909: 

 Male, Ventral Aspect. 



Female. — Scu- 

 tum, 1-56 to 1-62 

 millimetres i n 

 length by i -g milli- 

 metresbroad; very 

 conspicuous b e- 

 cause of its 

 whitish colour. 

 Cervical grooves 

 well developed. 

 Venter with punc- 

 tation and fine 



