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MILLIPEDS OF FAMILY LYSIOPETALIDAE LOOMIS 125 



radiating spinules; lower prong very short, located on the under side 

 of the arm and perpendicular to it. 



Males without velutinous pads on the under side of the last joint 

 of any legs. 



Type.— Male, U.S.N.M. no. 1244. 



Remarks. — Numerous specimens collected in Baboquivari Canyon 

 of the Baboquivari Mountains, Pima County, Ariz,, November 21, 

 1923, by H. F. Loomis. 



COLACTIS SIDERALIS, new species 



Figure 16, ;, A:; Plate 4, Figures 1, 2 



Diagnosis. — This species resembles saxetarm more closely in the 

 number of segments and the size and proportions of the body but 

 differs in the greater number of ocelli, the shape of the lateral carinae 

 and male gonopods, and in the greater number of male legs with a 

 pad beneath the last joint. In these latter characters it shows some 

 similarity with the considerably larger, more segmented protenta. 



Description. — Body moderately slender, the males more so than 

 the females and less flattened; 26 to 36 mm long and 1.8 to 2.5 mm 

 broad ; segments 55 to 68 in number (pi. 4, figs. 1, 2) . 



Eye cluster triangular-quadrate, with a few more ocelli than in 

 the other species, from 48 to 56 ocelli arranged in 8 or 9 rows ; sense 

 organ in front of rows 3, 4, and 5 of the ocelli. 



Segment 1 with 10 crests, the inner pair reaching the middle of the 

 segment but not beyond, the anterior ends slightly more separated 

 than the posterior ends ; the four inner crests closer together than the 

 outer ones ; the 10 anterior setae in a strongly triarcuate series. 



Transition to the full number of dorsal crests occurs on segment 16. 



Primary crests of the dorsum prominent, thickened, with the apex 

 nearly even and continuous, when viewed from the side, and with a 

 crowded series of quite large, round pits immediately below the top 

 on each side, and usually with a more irregular series containing 

 fewer pits just below the top row. Secondary crests low and slender, 

 the sides scaberulose or coarsely reticulated, as is the surface between 

 all ridges, but lacking distinct pits. Inner pair of secondary crests 

 reaching nearly to the posterior margin, the other secondary crests 

 not extending onto the posterior fourth of the segment. 



Lateral carinae prominent, in outline somewhat intermediate be- 

 tween those of hahoquivari and protenta, being less broadly rounded 

 and with a more distinct hind angle than in the latter, and more 

 broadly rounded and with a less acute hind angle than in the former, 

 and there are no large irregularities of the margin, as in saxetana 

 and quadrata (fig. 16, k). Pore located in an elliptical impressed 

 area occupying nearly all the lateral margin of the carinae on the 



