I06 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I25 



greatest at segment 6 which is 1.3 times the width of segments 1-4. 

 Body seems to gradually widen from head through the seventh ab- 

 dominal segment, posterior to which it again tapers ; abdomen oval in 

 cross section, wider than high ; in profile, the ventral surface of seg- 

 ments 6-8 slopes upward and the dorsal surface slopes downward. 

 General color gray to tan, with definite darkened collar across an- 

 terior end of thorax and with ventral surface of pseudopod also dark- 

 ened ; no dark patches on ventrolateral regions of segments 6 and 7. 



Head: Designs on frons-clypeus and epicranial plates shown on 

 plate 40, figure 359. Each cephalic fan with 34-40 pectinate branches, 

 the hairs on these branches close together, simple, and fine, intermixed 

 at regular intervals with heavier, longer hairs. Mandible with 11 

 teeth on its inner margin ; the 3 apical teeth larger than any of the 

 others, the second and third appearing to emerge from a common base ; 

 the most basal tooth is somewhat removed from any of the others 

 which are contiguous to one another and of variable length. Antenna 

 340 /u, long, 4-segmented, dark yellow, not reaching the end of the basal 

 stalk of cephalic fan ; segment 3 almost equal to length of segments 

 I and 2 taken together ; segment i with longitudinal striations. Sub- 

 mentum with 17 apical teeth arranged in groups of 3-3-1-3-1-3-3, all 

 but the lateral groups of three somewhat extended from the apical 

 margin ; ventrolateral row with 7 hairs in irregular arrangement ; all 

 hairs appear bifid from their middle to the apex, the outer half also 

 darker; lateral margin of submentum irregularly serrated. No oc- 

 cipital cleft (pi. 42, fig. 396). 



Thorax and Abdomen : Pseudopod (thoracic proleg) with 66-76 

 rows of hooks on its apex ; postclypeal sclerites long and narrow, only 

 lightly sclerotized, appearing to extend from the posterior junction of 

 the frons-clypeus with the epicranial plates ; inner end pointed. 

 Posterior sucker with 126-134 rows of hooks. Anal gills composed 

 of 3 short, digitate processes, somewhat expanded distally. Anterior 

 arms of X-shaped sclerite more heavily sclerotized than the posterior 

 arms ; a small, triangular-shaped patch between the anterior and 

 posterior arm of each side, each patch with a central clear area; 

 posterior arms completely encircling the posterior sucker; no rectal 

 scales. Eighth segment without ventral papillae or sclerotized plaques. 



Types. — Pupa, in collection of J. Romeo de Leon ; collected in a 

 stream at Aguas Amargas, Zunil, Department of Quezaltenango, 

 Guatemala, at 1,800 meters above sea level. Plesiotypes, 2 5$, ii^ 

 collection of Herbert T. Dalmat, were collected in the type locality. 

 Amongst the (^^ used for the above description, are 4Q-2 (4 slides) 

 and R-6A (3 slides) which are also designated as plesiotypes; they 

 are in the author's collection. 



