That the wide range of adult size and appearance (scutal 

 smoothness, degree of punctation, depth of lateral grooves, pres- 

 ence of hairs on basis capittili, presence of dorsal concavity of 

 palpi, shape of adanal shields, presence of accessory shields, 

 size and shape of tarsi and of porose areas, etc.) is due to 

 variation in fullness of feeding of the immature stages has been 

 convincingly presented by Nuttall (1913). 



It appears, however, that no matter how variable this species 

 may be, it is seldom difficult to distinguish from other species. 



When maJcing the rather sizeable collections of R. appendicxi - 

 latus at Kajo Kaji and Yei, in December of 1951, it was noted 

 that specimens from the ears of cattle were consistently of rather 

 ■uniform size and similar in structure and appearance. But spec- 

 imens from sheep and goats varied considerably in size and struc- 

 tvire, and many were malformed. Upon returning to Yei in December 

 of 1952, additional specimens were obtained from cattle. Many 

 of these were as variable and misshapen as the previous year's 

 collections from goats and sheep. The factors behind these dif- 

 ferences are too complex to allow conjecture over the reason, 

 interesting as it might be to do so. It is suggested, however, 

 that other reasons, besides immature stage nutrition, may draaa- 

 tically influence the parasite's well-being and shoxild be inves- 

 tigated. 



IDENTIFICATION 



Males vary in overall length from 1.8 mm. to A.^ mm.; "normal " 

 males are 3.0 mm. or above in length. They are usually brownish 

 or reddish- brown, but may be very dark; the legs are always red- 

 dish-brown. The clearly-defined dorsal process of coxa I res- 

 tricts this species to a rather small group among which it can 

 be distinguished by the deep, long lateral grooves, peculiar 

 scutal punctation, shape and rounded posterior margins of adanal 

 shields, flat eyes, etc. Scutal punctations of moderate size 

 are evenly spaced in the central area of the scutum but almost 

 or entirely disappear in the lateral fields and outside of the 

 lateral grooves. Posteromedian and paramedian grooves are narrow 

 but distinct and the cervical fields are more or less reticulate, 

 especially in large specimens. A caudal process is sometimes 



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