534 bulletin: museum of comparative zoology. 



articles. First three articles moderate, the others short and very short. 

 Ultimate article short, rounded, subequal to or a little shorter than the 

 two preceding ones taken together. 



Ocelli in tvpe 8 to 11 arranged in 3 or 4 series: e. g., 1+1, 3, 3; 

 1 + 1, 3, 3, 1; 1 + 3, 4, 3; 1 + 1, 3, 3, 2. Singles ocellus largest, 

 separated. Others not very distinct. Organ of Tomosvary in out- 

 line smaller than the seriate ocelli. 



Prosternum near 1.77 times wider than long. Distance between 

 chitinous spots about 1.77+ times width at level of bottom of sinus; 

 only 2.2 times the dental line. Teeth 3 + 3 or 3 + 4; not much 

 differing in size; line of apices on each side a little convex with 

 angle between lines at middle thus reentrant. Sinus shallow, broadly 

 U-shaped or subsemicircular. Spine slender and short, on a tubercle 

 just ectad of outer tooth. Margin evenly convexly rounding back 

 from spine to prehensor on each side. 



First dorsal plate in measured specimen 1.56 times wider than long. 

 Sides between corners straight or toward middle of length a little 

 incurved, only moderately converging. Posterior angles of ninth, 

 eleventh, and thirteenth dorsal plates produced; the processes narrow 

 and not long, those of ninth plate shortest. 



Coxal pores moderately large, somewhat transversely elongate or 

 subelliptic, decreasing on each coxa proximad: 5, 4, 4, 4; 5, 5, 5, 5. 



Claw of female gonopods long, subacute, moderately curved. 

 Spines 2 + 2, stout and rather short, of the usual subconical form. 

 Mesal edge of first article sharp, strongly chitinized, conspicuously 

 bending out ectad proximally. 



Spines of first legs, ^ ^ o' o' i ' of the second, ^Yolh.' ^^ ^^® third and 

 fourth, q' q' q' ^' ^ ; of the fifth, q'^'^'^'^ ; of the sixth and seventh, pp'^'^'^ ; 

 of the eighth to twelfth, ^ ^ 2' 2' 2 ' ®^ ^^^ tliirteenth, q'^'^'^'^ ; of the 

 penult, Q j' 2' 9*2 ? of the anal, I' "' 2' 2 ■> > d^-ws 2. Anal coxae laterally 

 armed but the spine seemingly easily lost. The single dorsal tibial 

 spine is in all cases on the anterior side. 



Segments of legs longitudinally furrowed dorsally and ventrally, 

 especially on the more posterior pairs. 



Anal legs of male not specially modified. Penult legs with the fifth 

 article at distal end on mesal surface presenting a longitudinally 

 placed, pilose swelling or lobe somewhat similar to but proportionately 

 larger than that borne on the corresponding article in males of Guam- 

 bius. 



Length 19-21 mm.; greatest width of tergites 2.25 to 2.6 mm. 



Locality. — Mexico: Hidalgo, Guerrero Mills (W. M. Mann). 

 Type, M. C. Z.. 1740; two specimens. Type and Paratype, M. C. Z. 

 1752. 



