720 



ARTHROPOD A 



The replete female is 9 by 5 millimetres; scutum oval, larger than 

 wide. Second segment of palpi long and spiny. 



Life-History. — The larva, after feeding, drops off the dog, and 

 moults. The nymph attacks another dog, feeds, drops off, and 

 moults. The adult attacks a third dog, feeds, drops off. and lays 

 eggs which develop larvae. 



Pathogenicity. — It is the spreader oiPiroplasma cams among dogs, 

 causing their biliary fever. Nuttall and Hadwen have shown that 

 this canine piroplasmosis can be successfully treated by hypodermic 

 injections of 6 c.c. of a i per cent, solution of trypanrot, or 4-5 to 

 5 '5 c.c. of a saturated solution of trypanblau. 



Subfamily IxoDiNiE. 



The following diagnostic table, modified slightly from Salmon 

 and Stiles, will indicate the genera: — 



A. Eyes absent : — 



I. Pre-anal crescentic groove opens posteriorly: — 



(a) Palpi valvate — Ixodes (Fig. 331). 



(b) Palpi clavate — Eschatocephalus. 



IL Post-anal crescentic groove open anteriorly — Apo- 



nomma. (Fig. 333). 

 in. Without anal groove in the female; one anal shield in 

 the m.?i\^—Ceratixodes. 



B. Eyes present: — 



I. Anal plates absent — Amhlyomma (Fig. 336). 

 II. Anal plates present on males — Hyalomma (Fig. 339). 



Ixodes Latreille, 1796. 



Synonyms. — Cynorlmstes Hermann, 1804; Oo^ow^/s Dumeril, 1822. 



Ixodinae without eyes, and with long palpi hollowed on the internal 

 surface. Tarsi without terminal spurs. Pre-anal groove open 

 posteriorly. 



Male with scutum not covering the lateral and posterior margins: 

 no festoons; stigmata oval. Ventral shields seven in number; 

 one pregenital, one median, two epimeral, one anal, and two 

 adanal. 



Female with three dorsal longitudinal grooves and two longi- 

 tudinal genital grooves ventral, and the anal crescentic groove 

 already mentioned. 



Type Species. — Ixodes ricinus Linnaeus, 1758. 



Ixodes ricinus Linnaeus, 1758. 

 Synonyms.' — Acarus reduvius Linnaeus, 1758; A. ricinus Linnaeus, 

 1758. 



This is the castor-oil tick, and is found in Europe, North Africa, 

 and North America on man, sheep, goats, cattle, horses, dogs, cats, 

 rabbits, bats, birds, etc. 



