538 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
mally but excavation short and not deep and sometimes concealed; 
a narrow furrow across base of article. Excavation not always 
evident, especially in younger specimens. 
Anal legs in male not especially crassate; fifth article at distal end 
on dorsal surface toward the mesal side with a conspicuous, laterally 
compressed and longitudinally placed crest which in side view is 
subtriangular, with dorsal surface convex and caudal end highest. 
Spines of first legs, Toe os ; of the second the same as first or eek 
of the third, 5 ; ; ; ;; of the fourth, ea of the fifth, Sanna of 
the sixth, aOneat of the seventh, 5 : ; - - or ventral spines, 0, 0, 0, 2, 2; 
of the eighth, nee or ventral spines 0, 0, 1, 3, 2; of the ninth, 
0, 0, 2, 2,2 
occa oo Or ventral spines 0, 0, 2, 3, 2; of the tenth 0, Oy 262. GF the 
? 0,.0,12, 3,0? es 
eleventh and twelfth, °°”. of the thirteenth, 2%”? . of the 
? 0,0, 3, 3, 2 > 0,0, 1, 3, 3, 2 
0,0, 3, 2, 2 
0, 0, 3, 2, 1 0, 0, 3, 4, 0 
fourteenth, Wace claws 3; of the anal, Ciao OF oan oe claws 3, 
the inner accessory large, the outer one small but distinct. Last four 
pairs of coxae laterally armed, but none armed dorsally. 
Length 10-13 mm.; width of tenth plate 1.9 to 2.5 mm. 
LocaLities.— Mexico; Hidalgo; Guerrero Mills; San Miguel; 
Pachuca (W.M. Mann). Typn, M. C. Z. 1737; eighteen specimens, 
Type, Paratypes, M. C. Z. 1751, and M. C. Z. 1738, 1739. 
This species is notable for the relatively great width of the body in 
the posterior region. 
LABROBIUS DELUS, sp. nov. 
Dorsum from light to dark brown. Head of similar shade but color 
typically deeper. Antennae brown proximally, paler distad. Pro- 
sternum and prehensors clear brown. Venter paler brown, the caudal 
plates darker as usual. Legs light brown, the posterior pairs a little 
more brightly pigmented. | 
Body moderately narrowed cephalad to the first plate, which is 
clearly narrower than the plate and much narrower than the head. 
Widths of head and of first, third, eighth, tenth, and twelfth plates 
to each other as 74 : 63:67 :80:80: 74. 
Head subcircular. Wider than long in ratio 37:35. Marginal 
breaks only obscurely indicated. Caudal margin nearly straight or 
very weakly incurved. The usual median sulcus in front of the suture 
and two longitudinal ones on caudal portion. 
Antennae rather short. Composed of 29 to 36 articles. Articles 
