NO. 1164. AMERICAN MEROCHKTA— COOK. 455 



ONISCODESMUS MICRURUS, new species. 

 (I'lnto XXIX, W^TH. 2a-2k.) 



Type. — No. 296, Berlin Museum. 



Locality. — liogotu, Colombia. 



Lenjjtli, about 10 mm.; width, 1.1 mm. 



('olor in a](;oliol, lij»ht lioni brown. 



Vertex rather Hat, without liairs, sulcus rather shallow; clypeus 

 sparsely hairy, densely ruj^uloKe transversely, antennii- rather densely 

 l)il()so, especially distad. 



r'irst seginent subrcniform, about twice as broad as lon^^, the ante- 

 rior margin sli{j;htly concave, the posterior strongly convex; only the 

 anterior corners are developed, and these are rounded; behind the 

 anterior margin is a transverse row of about six slight, broadly rounded 

 prominences. 



Second segment with large, spatulate, broadly rounded carina', much 

 exceeding in size, and extending far below those of the other segments. 

 The lateral and anterior margins are raised, and behind the anterior 

 margin is a prominent transverse ridge extending obliquely mesad, 

 but interrui)ted medianly by a distinct longitiulinal imjuession. 



Third and subsecpient segments with narrowly triangular cariuie, 

 becoming broader and more rounded caudad; surface of segments 

 smooth, convex; i)arallel to the posterior margin is a transverse, some- 

 what irregular sulcus limiting a row of more or less rectanguhir con- 

 vex areas present on all segments from the second to the eighteenth, 

 but less distinct on those of the i)osterior end of thc! body. 



Kepugnatorial pores small, hx^ated near the mi<ldle of the carina*, 

 not far from their bases. 



Supplementary margin wanting. The posterior edge of the dorsal 

 part of the segment is produced beyond the actual rim of the body 

 cylinder, so that the supplementary margin, if present, would not be 

 visible from above. Another unusual adaptation is seen in the fact 

 that this rim is deeply and broadly enuirginate opposite the insertion 

 of the legs, allowing the segments to be fitted against each other more 

 compactly than when the (cylindrical form of the individual segments 

 remains complete. 



Segment 11) with very broad semicircular carina',, separated from 

 each other only by a narrow slit, so that the last segment is from above 

 almost entirely concealed, being considerably shorter than segnient 19. 



Last segment greatly reduced, the apex, which i)roiects beyond the 

 anal valves, being merely a somewhat round(Ml tubei<!le bearing a few 

 seta;. 



Anal valves flat, scarcely margined; sujjerior setiferous tubercles 

 rudimentary, the seta; located near the superior corner of the valves; 

 inferior setaj on slight tubercles above the middle of the valves. 



