since this falls in the province of more complete, overall taxonomic 

 studies. For serious studies, specimens rather than vrritten descripi. 

 tions are almost invariably required, 



A word of explanation is due concerning the absence of species 

 diagnosis for immature stages of ticks treated in this report. Often, 

 when collections are made from hosts of smaller size, the only ticks 

 on them are immature and the difficulty or impossibility of identic 

 fying them is most discoxiraging. Larvae and nymphs of about half the 

 Sudan tick species have been described, but those of even fewer spe- 

 cies can be distinguished from all others with any degree of confix 

 dence. The inclusion of what we do know would be of little practical 

 value, except to a very few most highly specialized students. Any- 

 one favorably situated in this area with resources for rearing pro- 

 geny from known, isolated female ticks can make valuable contribiu 

 tions in this respect. At the present time. Dr. Theiler and I are 

 gathering data on this subject which will be published as soon as 

 we have sufficient information to make a utilitarian report. 



In morphological terminology, I have followed almost entirely 

 the usage of Cooley (19^6) and Cooley and Kohls (19A^), except that 

 I have substituted the word '"segment'" for '"article'* as used by these 

 authors. Where Kohls has recently modified some designations, I 

 have followed his lead. Cooley and Kohls' terras have not been ex:- 

 tensive enough for adequate description of Rhipicephalus species, 

 and I have been forced to add to them. Unfortunately, some termi— 

 nology used by British, American, and other workers differs or con- 

 flicts. An International Committee needs be called to decide a 

 standard set of morphological terms for the gross description of 

 ticks. The problem is reasonably simple and coxild easily be settled. 

 Consideration should also be given to standardizing insofar as possi- 

 ble the morphological terms used for mites and ticks. Reference to 

 terras appearing in this report is provided in various text fig\ares. 



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