90 EAST AFRICAN POLYDESMOIDEA— COOK. vol. xvm. 



Lateral carinse directed liorizontally, so that tlie dorsum appears 

 less convex than in mossamhicns. The submarg-inal ridges and the pos- 

 terior spinous pointed corner are more deveh>ped. 



Sterna of sixth and fifteenth segments, male genitalia, and colors as 

 in yiiossamhicus. 



Length, 5.") mm.; width, 11.4mm. 



Loealiti/. — Rios de Sena, near the Zambesi. Dr. Peters collected three 

 male specimens, and at first considered them a variety of mossambicus. 



AULODESMUS LAXUS (Gerstacker). 

 (PL II; tigs. IL', 13.) 



Euri/dcsniKu lu.rus, Gerstacker, Deckeu's Eeise, p. 518, 1873 



Slender, loosely articulated, slightly convex. 



Head and antennjie as in A. oxygonus. 



Clypeus with a rounded swollen su[)ra-labral ridge. 



First segment longer and somewhat narrower, the posterior margin, 

 as on the two following, without a fold li Ice thickening, from the median 

 slope strongly decurved and directed cephalad. On this account the 

 lateral margin is shorter and more oblique to the head. Without form- 

 ing a corner, and merely with a slight curve, it merges into the anterior 

 margin. The smooth ridges on the upper side of the lateral margins 

 are, and even more in the second segment, markedly smaller than in 

 A. oxygonus. 



The fiattened arch of the median part of the segments and the slight 

 elevation of the carinaj as in A. oxygonus, although on the second ami 

 third segments the elevation of the cariuie is evidently shorter, result- 

 ing from the fact that the anterior margin passes into the lateral by a 

 stronger curve. 



Posterior segments with the cariniie more pointed and farther i)ro- 

 duced caudad than in A. oxygonus; the carin;ii of the penultimate seg- 

 ment have the form of a small and lightly curved spine. 



Last segment with the cylindrical apical part separated by a deej) 

 transverse furrow and truncate at apex. 



Preaual scale without a median projectio'i between the wart-like proc- 

 esses. Anal valves with smooth, swollen margins. 



Posterior legs with two basal joints sparsely covered with small, 

 wart-like prominences. 



Sternum of sixth segment with an obliquely upright process almost 

 in the form of a spherical triangle, with a well-defined shining brown 

 terminal knob. 



Sternum of the fourth from the last pair of legs with a fiattened, 

 longitudinally furrowed process, nearly equilaterally triangular, bhiut- 

 poiuted, pitch-brown. 



First and second joints of posterior legs of male only sparsely beset 

 with snuill, wart-like prominences. 



