It should be noted that some gradation appears between the 

 two African subspecies of H. leachii and that a few specimens do 

 not conform strictly to the criteria for one or the other form. 

 The third subspecies, indie a Warburt'on, 1910 of southern Asia, 

 is more like the subspecies miihsami than like the subspecies 

 leachii , and is distinguishable from both by minor but apparently 

 constant and valid characters. 



Dr. G. Theiler and the writer for several years have been 

 collaborating on a morphological study of considerable series of 

 this species from a variety of hosts and localities. The results, 

 with complete data, will be presented in a separate report. The 

 variety humerosoides , common on canines, informally proposed b^' 

 Theiler U943BJ for the large, narrow, elongate form with extreme 

 ventral projection of spurs, appears from this study to be an 

 extreme body fonn of the somewhat variable H. 1. leachii and not 

 a separate morphological or biological subspecies"! In numerous 

 long series of specimens from single hosts, gradations from this 

 to less extremely narrow and elongate forms occur. There are, 

 however, sviggestions that the extreme form is a reflection of 

 particular host factors, and application of some of the more com- 

 plex aspects of newer taxonomic concepts may eventually justify 

 the name humerosoides. 



IDENTIFICATION 



Males . This long, narrow tick has tarsi II to IV gradually 

 tapering; punctations numerous, mostly small, and discrete; palpi 

 obtusely angled and widely triangtilar, widest at level of basal 

 third, with lateral margin straight or very slightly convex but 

 almost never concave; basally both dorsally and ventrally forming 

 a conspicuous and usually strong spur just laterad of the point 

 of insertion; palpal segment 3 with a retrograde spur that is 

 long and tapering; basis capituli with lateral margins varying 

 from almost parallel to somewhat divergent anteriorly and with 

 comua. that are usually large and pointed; coxae always with a 

 distinct basal spur overlapping the basal margin and with a 

 number of long, conspicuous hairs. This combination of characters 

 must be considered in separating males from those of other species 

 and from the subspecies muhsami. 



- 37/!. - 



