140 



Genus Ixodes 



42. 



43. 



44. 



45. 



46. 



Scapulae loDg and sharp ; basis capituli broadest 

 anteriorly (Mexico) 



Scapulae short and rounded ; basis capituli tri- 

 angular (America) 



(Scutum nearly twice as long as broad (1*3 x 7 mm.) 

 with rounded sides (S. America) 

 Scutum less elongate, with angular sides 



/'Anal grooves not reaching posterior border ; 



strong white hairs on scutum (on birds) 

 I Anal grooves reaching posterior border ; scutal . 

 V hairs short or absent 



Basis capituli broader than long; porose areas 

 almost confluent ...... 



Basis capituli longer than broad ; porose areas 

 separate . . . . . 



Sharp auriculae ; anal grooves rounded in front 

 (on mouse, Christmas Island) .... 



No auriculae ; anal grooves pointed in front 

 (America) . 



Nymphs. 



N.B. Of the 22 nymphal forms recorded there are 19 species 

 described sufficiently to be included in the following key. Not included 

 arefuscipes, p. 170 ; brunneus, p. 190 ; simplex, p. 208. 



With legs inordinately long 

 „ „ otherwise 



1. 



(Scutum without cervical grooves 

 1 » with 



(Scutum with lateral grooves 



I „ without lateral grooves . 



(Coxae unarmed .... 

 ( „ armed .... 



(Palp with article 1 large and pointing forward 

 1 » „ „ „ otherwise 



J With anal grooves fused to a point behind . 

 ( >, h ., otherwise . , , 



