1912] Chilopods and Diplopods 153 
Coxal pores very small, 2, 3, 3, 2. 
Ultimate pair of coxz armed laterally, the ultimate and_penult 
pairs armed dorsally. 
Spines of first legs 2, 3, 2; of the penult 1, 3, 3, 2, the claw single; of 
the ultimate 1, 3, 2, 1, the claw single. 
Anal legs of male long and slender the fourth, fifth and sixth joints 
longitudinally furrowed on ectal surface, laterally compressed. 
Length. 
Locality: Marshall, Colorado (Prof. T. D. A. Cockerell). 
One male specimen. 
Genus Poabius gen nov. 
Type.—Poabius verdescens Chamberlin. 
Other known species belonging to this genus are bilabiatus Wood, 
pitophilus Chamberlin, sokovus Chamberlin, clavigerens Chamberlin, 
utahensis Chamberlin, yukus sp. n., and the two new species described 
below. 
Poabius nankus sp. nov. 
Light. orange brown, caudal borders of major scuta darker; head 
somewhat darker caudad of frontal suture. Antenne and legs yellow. 
Venter yellow, the prosternum and caudal segments a little darker. 
Body markedly attenuated from tenth dorsal plate cephalad. Most 
dorsal plates with a strong median furrow which may be doubled and, 
on each side, one or two approximate lateral ones diverging from it 
caudad; within each lateral margin a furrow or sulcus running from near 
anterior edge at first near to and subparallel with the lateral margin and 
then bending away from it caudo-mesad to end at the transverse furrow 
which traverses most plates a little cephalad of caudal margin. 
Head subcordiform; caudal margin nearly straight; distinctly 
margined caudally and along cauda-lateral angles; a short transverse 
sulcus a little cephalad of caudal margin and between this and the frontal 
suture a median and several lateral pairs of longitudinal impressed 
lines or sulci. 
Antenne moderately short, composed of twenty more or less uniform 
articles. 
Ocelli pale, small, fifteen or sixteen in number arranged in four 
straight and regular series; thus, 1++5, 4, 4, 1 (2). 
Prosternal teeth dark, low, 2+2. 
Angles of none of the dorsal plates produced. 
Coxal pores circular, the edges weakly chitinized; 2, 3, 3, 2. 
Last two pairs of coxe laterally armed; the last three pairs dorsally 
armed. 
Spines of the first legs 1, 3, 2; of the penult, 1, 3, 3, 2, armed with 
three claws; of the anal 1, 3, 2, 1, the claw single. 
Gonopods of female with the claw tripartite; basal spines 2+2. 
In the male the anal legs have the prefemur elevated into a rim-like 
structure on dorsal or dorso-mesal side at distal end, and the femur 
bears at the proximal end on same side an ear-shaped process which is 
