RALPH V. CHAMBERLIN 193 



Aphelidesmus sp. 



Locality. — La Emilia. 



A single immature female specimen from a bromeliad along with 

 Aphelidesmus calverti, which species it resembles in coloration but 

 with polygonal areas outlined on prozonite and metazonite as 

 in A. intermedius, the limiting paler lines not at all impressed. 

 Antennae less clavate than in A. calverti. 

 Aphelidesmus sp. 



Locality. — Juan Vinas: Reventazon Road (February 15, 1910). 

 A very young female of uncertain species. 



CHELODESMIDAE 



Aceratophyllus dux sp. nov. 



Dorsum between keels brown ; a deeper brown circular spot just proximad 

 of each keel; the keels and caudal border of metazonites more yellowish 

 brown and in part of dilute orange caste; an interrupted longitudinal median 

 dorsal dark line over caudal half of body. Distal half of sixth article of 

 antennae rufous. Legs light brown. 



Vertex of head glabrous; crossed by a sharply impressed sulcus which 

 extends to level of antennae. On each side of sulcus in upper frontal region 

 a pair of setigerousfoveolae; bristles present below this level, these increas- 

 ing in length and number ventrad, the lower ones long. 



Antennae long; fifth and sixth articles distinctly the longest. 

 First dorsal plate much wider than the head. Anterior margin mesally 

 straight, at ends curving back about the rounded anterior corners. Caudal 

 corners subrectangular. 



Second dorsal plate with anterior corners also rounded; a single small 

 tooth on ectal side of corner; caudal corners rectangular or slightly pro- 

 duced caudad. The immediately succeeding plates similar but anterior 

 corner more angular, the single tooth at or near corner present in all. The 

 pore-bearing plates with edge conspicuously thickened about pore, the 

 thickening regularly decreasing from pore toward each corner. In pro- 

 ceeding caudad the plates increase in size and their caudal corners become 

 more and more produced, the processes in the most caudal ones moderately 

 long and acute. In all tergites the keels are bent up dorsad so that their 

 lateral edges are above level of median portion of tergites. 



Anal tergite with distal portion bluntly rounded or with the median 

 apical portion truncate; bearing 2 shorter and 2 very long bristles at tip, 

 a pair farther proximad and a pair of short ones on ventral side. Proximal 

 subtriangular portion with a pair of long bristles near each lateral margin. 

 Anal valves with mesal border strongly margined. Two bristles just 

 ectad of elevated margin on each valve. 



Anal scale with caudal margin evenly convex; bearing a long bristle a 

 short distance each side of median line. 



TRANS. AM. ENT. SOC, XL. 



