MILLIPEDS OF FAMILY LYSIOPETALIDAE — ^LOOMIS 113 



DIACTIS SOLEATA, new species 



FiGUKE 17, &-e; Plate 3, Fiqxire 1 



Body moderately slender, somewhat depressed; 19 to 27 mm long 

 and 1.3 to 2 mm wide; nmiiber of segments 48 to 54 (pi. 3, fig. 1). 



Eyes composed of 42 to 48 ocelli in 8 or 9 rows, counting down- 

 ward from the top of the head ; sense organ large, opposite the an- 

 terior ends of rows 6 and 7, or 7 and 8, and invading the triangular 

 outline of the eye. 



First segment with 18 low crests not exceeding the basal fifth at 

 the middle of the hind margin; lateral crests scarcely longer than 

 those at middle; inner primary crests oblique, the anterior ends 

 almost meeting but the posterior ends widely separated ; no secondary 

 crests between the median primary crests. 



Segments 2 to 4 with the inner pair of primary crests very strongly 

 divergent on each segment, the posterior ends of the crests six to 

 eight times as widely separated as the anterior ends. Median pair 

 of secondary crests present on segment 2 and succeeding segments. 



Transition to the full number of crests occurs on segment 8. 



Primary crests more prominent on the last segments than on those 

 in front. Secondary crests occasionally not reaching the posterior 

 margin of the segments; the inner pair more apt to be shortened 

 than any others. On the posterior segments the secondary crests are 

 much fainter than on the middle segments. Setae at the posterior 

 ends of the primary crests are longer than in any other American 

 member of the family ; nearly half as long as the crests, while on the 

 caudal segments the setae are as long as or longer than the crests. 

 Apex of the crests smooth and continuous; the sides of the crests 

 and the intervals between crests marked with fine reticulations visi- 

 ble under strong magnification. 



Poriferous carinae projecting little more than the primary dorsal 

 crests but w4th the lateral margin thickened and with the impressed 

 pore area occupying the entire margin on all but a few of the ante- 

 rior segments. Pores located in front of the middle of the impres- 

 sion. Below the pore carinae are two primary crests, which are 

 higher than the carinae or any of the dorsal crests. 



Last segment narrowdy rounded-truncate at apex, the surface 

 without crests but with six setiferous tubercles. 



Males with the gonopods erect (fig. 17, 5, c) ; the lower half of 

 each very slender ; the upper half more expanded, ending in a small 

 S-shaped hook directed forward and outward, below the hook and 

 in front of it is a short 2-pronged arm wdth the prongs widely 

 spreading; from the lower anterior part of the apical expansion a 

 large, rather long, slightly curved and concave lobe is directed down- 



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