IXODES. 



Ixodes Ricinus: Variegated color like castor oil bean, — black, brown, 

 yellow ; external mandibular apophysis with five teeth (7 or 8 in male) in- 

 creasing backward ; dart has teeth increasing in size backward. Distribu- 

 tion : Europe, N. Africa, America. Hosts : Sheep, cattle, goats, horses, 

 deer, hare, rabbit, dog, cat, fox, ferret, hedgehog, bat, bird, man, etc. Prob- 

 ably conveys louping'-itt. I. Hexagonus, I. Reduvius : Size and form of 

 I. Ricinus : dart with central row of teeth on each side largest though less 

 numerous, shorter legs than ricinus, venter hairy. 



Ixodes Ricinus, Castor-bean Tick. This familiar tick has 

 been named in accordance with the form, size and variegated color, 

 which strongly suggest the bean of the castor oil plant (Ricinus 

 Communis) . 



Female. When replete (ovigerous) may be 10 to 11 mm. by 

 6 to 7 mm., ash colored with marbling of black, brown or yellow. 

 Dorsal shield deep brownish chestnut, oval, subpentagonal, lateral 

 borders salient, posterior angle rounded, anterior slightly notched 

 for head, punctations small, uniform and regularly distributed, 

 hairs numerous, fine and short. Two anterior grooves divergent 

 posteriorly ; three posterior grooves, median and two lateral, the 

 latter concave centrad. Genital pore on plane of legs IV. Anus 

 with three hairs on each lip. Stigmal plate finely punctate, pore 

 small. Mandibles rough (shagreened) on sheath of stem, internal 

 apophysis elongate with two retrograde teeth (median and ter- 

 minal) ; external apophysis with five teeth encreasing in size from 

 the anterior to the posterior one. Dart (hypostome) lanceolate, 

 with three rows of teeth on each side. Legs thin and bearing stiff 

 hairs on each article. Coxae I bears a strong spine on the postero- 

 median angle. Tarsi long and thin, in I nearly one-third of the 

 leg. 



Male. Body oval, deep reddish-brown. Dorsal shield covers 

 entire dorsum except a thin marginal zone ; punctations very fine 

 and numerous. Genital pore opposite legs III. Pregenital shield 

 a third longer than broad, narrower, round or sinuous anteriorly, 

 convex laterally. Head (capitulum) 500 ;«. long. Mandibles 

 corrugated transversely on the sheath, internal apophysis with 

 three teeth— the median the largest, external apophysis with seven 

 or eight teeth encreasing in size from before backward. Dart 

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