MILLIPEDS OF PANAMA—LOOMIS 95 
Teinorhachis tenuis, new species 
FIuGRE 3c—h 
Houoryre: Male, USNM myriapod collection 2640, probably from 
Canal Zone (see family heading, p. 92), 1923, O. F. Cook. 
ParatyPsEs: Three 19-segmented females, author’s collection, same 
collection data as for holotype. 
Description: Male 18 mm. long, 1.7 mm. wide. Body slender, 
loose jointed, the prozonites especially exposed in midregion of body; 
body widest at segment 2 or 3, gradually narrowing thereafter; dorsum 
smooth, convex in female with lateral keels thick, narrow and pro- 
jecting just above middle line of sides; male more flattened with keels 
wider and nearly on level of dorsum; color destroyed by preservation. 
Legs exceeding keels by the four outer joints, joint 3 longest; sterna 
high, finely hispid, and nearly as wide as combined lengths of joints 
1 and 2 of legs. 
Head, from a short distance above antennae to the front margin, 
rather densely beset with fine erect hairs of various lengths; vertex 
without a median furrow in male but a strong one in females; antennae 
slender with joints 2 to 6 subequal in length and thickness (fig. 3c). 
Segment 1 sublunate, three times as wide as long, front margin with 
a raised rim followed by setae as shown in figure 3d. Ensuing seg- 
ments with a broad, indefinite transverse median depression in front 
of which are two erect setae; lateral keels of segments 2 to 4 thin and 
with both corners more squarely angular than ensuing ones; porif- 
erous keels through segment 14 wider and with outer margins and 
posterior angles more rounded than adjacent poreless keels (fig. 3e); 
from segment 15 backward keels have posterior angles increasingly 
produced to segment 18 on which keels are narrower, and those of 
segment 19 even less developed with posterior angles half as large as 
on segment 18; anterior corners of segments 2 to 6 with an outer 
tooth in male, a similar tooth present to segment 15 or 16 in female. 
Last segment long, the narrowed apical half longitudinally convex 
and sharply raised above the forward half; apex with four terminal 
setae; anal valves strongly inflated with thin, high margins; preanal 
scale shown in figure 3f. 
Gonopods as in figure 3g, relatively small, reaching forward only 
betweea the coxae of seventh legs. Pregenital legs of male with outer 
joint, especially on first three pairs, heavier than those following the 
gonopods and densely hairy beneath; third male leg and sternum 
shown in figure 3h. 
