68 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 68 



Soldier. — Head yellow (lighter colored than opacus), sides parallel 

 (slightly convex in middle), head slightly narrower anteriorly 

 (narrower head than opacus), rounded posteriorly, truncate ante- 

 riorly, an orange, median, longitudinal impression extending from 

 posterior margin to frontal gland and base of epicranial suture ; with 

 scattered, long hairs. Gula with sides parallel, broader in middle 

 than in opacus. 



Labrum yellow, elongate, narrow, trilobed at apex, narrowed at 

 base, follows outline of left mandible, long hairs at apex. 



Mandibles black, left longer than right, broad even at apex, right 

 slightly pointed at apex beyond curve where it fits into the left 

 mandible, left doubly curved, right nearly straight; mandibles 

 shorter but of same general shape as in opacus. 



Antenna light j^ellow-brown, 16 segments, with long hairs; third 

 segment only slightly longer than second (in opacus nearly twice 

 as long) ; fourth segment shorter than third ; segments become 

 longer and broader to apex; last segment elongate, narrow, sub- 

 elliptical. 



Pronotum white tinged with yellow, saddle-shaped, anterior mar- 

 gin broadly rounded, markedly emarginate, sides roundedly slope 

 to posterior margin which is nearly straight; with dense long hairs. 



Legs white, tinged with yellow, elongate slender, pubescent. 



Abdomen dirty gray-white, tinged with yellow, with dense long 

 hairs; cerci prominent. 



MeasureTnents. — 



Length of entire soldier, 9.00-10.00 mm. 

 Length of head with mandibles, 5.50 mm. 

 Length of head to anterior, 3.00-3.10 mm. 

 Length of left mandible, 2.50 mm. 

 Length of pronotum, O.GO mm. 

 Length of hind tibia, 1.45 mm. 

 Width of head posteriorly, 1.80-1.90 mm. 

 Width of head anteriorly, 1.70 mm. 

 Width of pronotum, 1.10 mm. 



C. (N.) pa7'aUelus Snyder is a lighter colored, smaller species than 

 opacus; there are also differences in antennal segmentation. Com- 

 pared with specimens of opacus determined by F. Silvestri. Silves- 

 tri's opacus, variety parvus, is not described with sufficient detail for 

 purposes of comparison, the soldier is smaller than parallelus; 

 parvus may be merely a biological variety of opacus. 



Type locality, — Rosario (Lake llogogua), Bolivia. 



Described from a series of winged female and male adults, soldiers 

 and workers, collected at the type locality by W. M. Mann. 



