46 University of MicJiigan 



Aphelidesmus guianensis, sp. no v. 



PI. i8, Figs. 1 19-122 



Dorsum with metazonites deep colored or blackish, the 

 prozonites in some degree lighter and the keels entirely pale 

 fulvous or, in types as preserved, nearly white. Last tergite 

 dark throughout. Legs and antennae light brown. 



Collum strongly narrowed laterad, the lateral lobe or keel 

 near its outer end only one-third as long as the middorsal line 

 of the plate, while at its base, i. c, near inner end of light 

 area, about two-thirds as long as that line. Anterolateral cor- 

 ner widely convex, the caudolateral more narrowly rounded 

 (PI. 18, Fig. 119.) 



In the second tergite the lateral margin of keels straight, 

 with the two angles in general outline rectangular, but the 

 outer edge of the anterior one produced ectad. In the third 

 tergite the caudolateral angle of keel moderately acute, the 

 outer edge of keel oblique and a little convex, the anterolat- 

 eral corner with ectal process smaller. In the fourth tergite 

 the outer edge of keel still more convex, with anterior comer 

 more rounded and the process or tooth still slighter and 

 rounded, scarcely evident, as shown in PI. 18, Fig. 120. 



Cauda with sides convex ; caudal margin obtusely notched 

 at middle. Anal scale very broadly shield-shaped, the sides 

 convex excepting at anterior end, where concave ; posterior 

 angle very obtuse. (PI. 18, Fig. 121.) 



In the male gonopods the tarstis characterized by bearing 

 a short, plate-like process on its caudal side. See further, 

 PI. 18, Fig. 121. 



Length of male type, 46 mm. ; width, 7 mm. 



British Guiana: Forested Sand Hills; Aug. 17, 1914; F. 



