594 



MEDICAL ENTOMOLOGY 



35. 



36. 



37. 



38. 



39. 



40. 



41. 



42. 



43. 



44. 



45. 



Scutum sub-triangular, palps slightly hollowed out internally 



(Ceratixodes) put us 



First segment of palp narrow, not ensheathing hypostome .... 36 

 First segment of palp broadened and ensheathing hypostome . tasmani 



(Australia; Tasmania.) 

 First segment of palp not prolonged . . . '. . . . . 37 



First segment of palp prolonged ventrally or laterally 40 



Scutum as broad as long, sub-circular, basis capituli without 

 horns , . 



japonensis. 



(Japan, Tokio.) 

 . . . 38 

 39 



Scutum longer than broad ......... 



Scutum a little longer than broad, legs of medium length 

 Scutum very much longer than broad, legs very long (Esch- 



atocephalus) vespertilionis 



Basis capituli with ventral hump behind each palp . . . rubicundus. 

 Basis capituli without ventral humps ..... simplex. 



(Shanghai; French Congo, Gaboon.) 

 First segment of palp in. the form of a transverse spur longer 



than broad . tenuirostris. 



First segment of palp with a hump on ventral surface, scutum 



much broader than long ornithorhynchi. 



(Tasmania.) 



Anal groove open posteriorly ....... 



Anal groove pointed posteriorly 



Basis capituli with ventral hump behind palp .... 



Basis capituli without ventral hump, anal groove prolonged 



behind in the form of a racket ...... 



Scutum as broad as long with superficial punctations and 



lateral groove, coxa I with a very short internal spurs 

 Scutum much longer than broad ; coxa I with a very well 



developed internal spur ....... 



Coxa I with nearly obsolete external spur, scutum with large 



punctations .,.,.,.... 



Coxa I with long external spur, scutum with fine punctations . 



42 

 45 

 43 



ugandanus. 

 pilosus. 



44 



schillings!. 



(Mozambique.) 

 lunatus. 



(Madagascar.) 

 holocyclus. 



Palps long, first segment not thick 



Palps short, first segment dilated, ensheathing the base of the 



hypostome , , , . . , , . . . australensis. 



(Australia.) 



Ticks of the genus Ixodes are widely distributed, and have been 

 recorded from Europe, Africa, Asia, Australia and North and South 

 America, the latter continent being specially rich in species. Only one 

 species, Ixodes acutitarus has been recorded from India (Darjeeling) ; 

 not a single species has been found in South India. 



Ixodes ricinus, L. Male. (Plate LXXVI, fig. 1.) Anal groove with 

 arms slightly divergent posteriorly. Coxa I with a well developed spur 

 overlapping coxa II. Tarsi long and slender, without dorsal humps. 



