chamberlin: chilopods from Mexico and west indies. 537 



Labrobius minor, sp. nov. 



Dorsum light brown to very deep brown or dull brownish black in 

 individuals in full color. Head concolorous with dorsum or nearly so. 

 Antennae deep colored like the head and either uniform, or, more 

 commonly paler, rufous distad. Prosternum and prehensors dark 

 brown but paler than the dorsum. Legs brown with tarsi, especially 

 in posterior pairs, lighter. 



Body unusually broad, varying from only four to sLx times longer than 

 widtl;i of the tenth dorsal plate. Body very strongly narrowed cephalad 

 to the first plate. Widths of head and of first, third, eighth, tenth, 

 and twelfth dorsal plates to each other as 79 : 65 : 77 : 116 : 127 : 112. 



Head broad, laterally convex; widest at breaks which are weak; 

 anteriorly widely rounded; caudal margin straight. Clearly wider 

 than long, the ratio being close to 15:14. A distinct median longi- 

 tudinal sulcus in front of the suture; head elsewhere smooth. Hairs 

 in part short and in part long, straight. 



Antennae of intermediate length; becoming very thin distad. 

 Articles mostly 49 to 57 in number; of these the first three are moder- 

 ately large and the others very short and closely compacted. Ulti- 

 mate article clearlv longer than the two preceding ones taken together. 



OcelH 1 + 2, 4,X 2; 1 + 3, 3, 5, 2; 1 + 3, 3, 3, 3; 1 + 3, 4, 4, 1; 

 etc. The single ocellus distinctly largest, subcircular. Other ocelli 

 small, distinct and regular, with the second ocellus of top series nearly 

 always the largest. 



Prosternum with teeth 2 + 2, relatively close together; the inner 

 tooth of each pair larger than the outer one and the line of apices in 

 adults straight or nearly so. Spine slender, distally extremely fine, 

 inserted a little ectad of outer tooth on dorsal surface proximad of 

 edge. Anterior margin extending a considerable distance ectad from 

 outer tooth almost horizontally and then bending abruptly back and 

 but little ectad of directly caudad, then curving out to prehensor: 

 1.57 times wider than long. Distance between chitinous spots 1.88 

 times width at level of sinus; and nearly four times the dental line. 



First dorsal plate short, strongly narrowed caudad; varying from 

 1.8 to 2.16 times wider than long. Posterior angles of the seventh, 

 ninth, eleventh, and thirteenth dorsal plates produced, the processes 

 broad with mesal side long and oblique. 



Coxal pores mostly 3, 4, 4, 3 or 3, 4, 4, 4, small. The porigerous 

 area usually depressed with an elevated rim along each side. 



Claw of female gonopods stout, relatively short, moderately curved, 

 broadest a little distad of base. Spines 2 + 2; of the usual sub- 

 conical form; the outer one of each pair a little longer than the inner. 

 Inner edge of first article strongly chitinized, sharp, excavated proxi- 



