never enoxigh to confuse the picture. Posteromedian and paramedian 

 grooves are absent; rarely they are just barely discernible, but 

 never pronounced. This latter fact is an important distinction 

 between R. s. simus and those specimens of R. s. sanguinevis that 

 otherwise closely approximate R. s. simus in appearance. The 

 scutum is arched and usually sliiny blax;k, less commonly reddish 

 brown or reddish yellow, with definite, deep lateral grooves and 

 clear festoons. The central festoon may protnide with engorge- 

 ment. A hxunp of coxa I projecting dorsally frequently is large 

 enough to resemble a pointed projection, but closer inspection 

 indicates its bluntness. Ventrally, the shape of the adanal 

 shields, with their rounded external and internal margins, is 

 usually characteristic; but in some specimens, in which they 

 are abnormally narrow and with a deeply concave inner margin, 

 they approach the sickleshape of the subspecies senegalensis . 

 Size is extremely variable, running from minute (1.9 mm. long _ 

 rarely) to well over 5.0 ram. long. 



Female ; The outline of the black (rarely reddish) scutum 

 is subcircular with a broadly roxuided, slightly sinuous posterior 

 margin; the length-width ratio is approximately equal or slightly 

 wider than long. Punctations are normally rare but may be some- 

 what heavier and more distinct than in the male. Interstitial 

 punctations are rare and inconspicuous, or absent; rarely they 

 are somewhat pronounced and slightly confuse the typical picture 

 of this species. Lateral grooves are of variable distinctness 

 and length; frequently they are extended posteriorly by a few 

 punctations; in some individuals they are much reduced. The 

 converging and thence diverging cervical grooves usually clearly 

 extend to or almost to the posterior margin, but may be obsolete 

 on the posterior third of the scutum. Lateral fields usually 

 contain two or three punctations; eyes are flat. Size is variable 

 with tremendously engorged individuals reaching 15.0 mm. in length. 



Most females are easily keyed but those with reduced lateral 

 grooves are apt to be confusing. Females of the subspecies simus 

 and senegalensis axe quite similar. 



The nymph and larva have been described and illustrated by 

 Theiler (19A3). 



- 752 _ 



