NO. 14 MILLIPEDS OF WEST INDIES AND GUIANA LOOMIS I3 



ORTHOPORUS TRACTUS, n. sp. 



A single female was collected in the Aripo Savannah, Trinidad, 

 February 14, 1932. 



Diagnosis. — The small size of the body and the median light stripe 

 extending its full length distinguish this species from other members 

 of the genus. 



D escription.— Length. 30 mm, width 2 mm. Number of segments 



51- 



Body with a very definite, uniformly narrow, longitudinal median 

 line of light color continuous from the front margin of segment i 

 to the apex of the last segment ; posterior quarter of segments trans- 

 parent but the remainder brownish, areolate with light spots. Head 

 areolate on the vertex, with a solid brown band between the eyes ; 

 remainder of the head and the antennae light colored. 



Head smooth and shining and with a median furrow visible on the 

 front of the vertex. Eyes composed of about 30 ocelli in 6 rows form- 

 ing a triangle. Structure of the gnathochilarium typical of the genus. 



First segment with two very strong lateral striae reaching from 

 the eye around to the posterior margin. Laterad of these is a sub- 

 marginal stria reaching from near the lower corner of the eye to the 

 posterior margin. 



Ensuing segments with a simple, very sharply impressed, transverse 

 median line on the front segments, but following segment 6 or 7 it 

 contains a single series of uniformly close-set, short, longitudinal 

 striae beginning well below the pores. Ventral striae not reaching 

 beyond the limits of the legs except on a few anterior segments. 

 Dorsally, the surface of the segments is brilliantly shining and very 

 sparsely and minutely aciculate-punctate. The front half of the an- 

 terior subsegments is finely striate-reticulate, but the posterior half is 

 less sculptured. 



Pores beginning on segment 6. 



Last segment ending in a thin, rounded-triangular production sur- 

 passed by the valves. Dorsal surface rather coarsely and densely 

 punctured, the sides smoother. 



Anal valves punctate throughout but more strongly so near the 

 smooth raised margins. 



The assignment of this species to the genus Orthoporus, on the 

 basis of only female characters, is somewhat tentative, and final judg- 

 ment must be withheld until a male is examined. 



Ty/)^.— U.S.N.M. no. 1089. 



