CHAMBERLIN: CHILOPODS FROM MEXICO AND WEST INDIES. 9533 
Prosternal teeth 3+ 3 (or 3+ 4). A sinus present, wide, and 
semicircularly rounded at bottom. Spines ectal in position, small and 
bristle like. 
Posterior angles of ninth, eleventh, and thirteenth dorsal plates 
produced. Fourteenth plate normal. 
Coxal pores circular; uniseriate. 
Claw of female gonopods long and entire. Spines 2 + 2, stout, 
‘subconical. 
Anal legs in male not specially modified but penult with fifth joint 
bearing at distal end on mesal or caudal surface a longitudinally 
placed swelling or crest suggesting that of species of Guanibius but 
proportionately larger and different in position. 
Posterior coxae either wholly unarmed, or the last two or three 
armed dorsally while the anal pair may also be armed laterally. 
Dorsal spines of anal legs 1 (0), 0, 3, 2,0; ventral, in genotype, 0, 1, 2, 
2,2; claws 2. Dorsal spines of penult legs 1, 0, 3, 2, 0 or 0, 0, 3, 2, 0. 
Ventral spines of first legs 0, 0, 0, 0, 1; dorsal 0, 0, 2,1, 1. First nine 
to thirteen pairs of legs with but a single dorsal tibial spine. 
Length averaging near 20 mm. 
GENoTYPE.— D. simplex, sp. nov. 
In lacking a median ventral spine on the third and fourth segments 
of all legs, this genus is unlike any other lithobioid known to the writer. 
DELOBIUS SIMPLEX, sp. Nov. 
Dorsum chestnut or with some of middle plates deep brown, with 
no distinct chestnut tinge; with irregular dusky streaks. Head like 
dorsum or color slightly clearer. Antennae dark brown proximally, 
paler and somewhat rufous distad.. Prosternum and_prehensors 
dilute chestnut, the latter of pale ferruginous cast distad. Venter 
light brown, the caudal plates darker. Legs brown; the posterior 
pairs darker, the tarsi, excepting proximal portion of first article, 
dilute ferruginous. 
Body in male type 8.5-+ times longer than width of tenth plate 
Width of head and of first, third, eighth, tenth, and twelfth plates 
to each other as 53:47:49: 56:55: 52. 
Head wider than long in about ratio 53:50. Head wider just back 
of eyes than at breaks. Caudal margin mesally weakly incurved. 
A longitudinal median sulcus which is deepest in front of frontal suture 
but which crosses the latter and is traceable to a transverse furrow 
some little distance in front of the caudal marginal thickening. 
Antennae short, not very slender distad. Composed of 36-38 
