CYDNIDAE OF THE WESTERN HEMISPHERE — FROESCHNER 627 



Type data. — Holotype female (BrM), "British Guiana: Essequibo 

 R., Moraballi Creek, 14-viii, 1929, Oxf. Univ. Expedn., B. M. 1929- 

 485." 



Discussion. — The peculiar, acutely triangular prostemal carinae 

 appear to be unique within the genus and suggested the trivial name. 



Dallasiellus {Dallasiellus) viduus (St&l), new combination 



Plate figure 283 



Aethzis viduus St&l, 1860, p. 13.— Walker, 1867, p. 153. 

 Macroscytus viduus St&l, 1876, p. 19. 



Geotomus viduus Signoret, 1883, p. 45, pi. 3, fig. 154. — Lethierry and Severin, 

 1893, p. 74. 



Diagnosis.— The absence of large punctures on the disc of the 

 scutellum plus the presence of but one submarginal setigerous punc- 

 ture on each jugum will separate viduus from all others in the sub- 

 genus. 



Description. — From two males and three females. 



Male: Elongate-oval. 



Head: Length more than half width, 0.64(0.64-0.65): 1.04(1.03- 

 1.06); interocular width, 0.64(0.63-0.65); anterior outline subsemi- 

 circular, clypeus as long as juga, somewhat narrowed apically; surface 

 slightly convex, impunctate; jugum with one submarginal setigerous 

 puncture immediately anterior to eye; ocelli moderate, separated from 

 eye by space about two times transverse ocellar width; jugum ven- 

 trally polished, impunctate; maxillary plate alutaceous and with few 

 punctures on basal third. An tennal segments : I, 0.21(0.20-0.23); II, 

 0.23(0.20-0.26); III, 0.33(0.32-0.34); IV, 0.55(0.50-0.60); V, 0.55 

 (0.50-0.60). Bucculae about as high as labial II; labium reaching 

 between middle coxae. Labial segments: I, 0.35(0.34-0.86); II, 

 0.66(0.66-0.66); III, 0.47(0.44-0.50); IV, 0.33(0.30-0.36). 



Pronotum: Length about half width, 1.17(1. 17-1. 17):2.23(2.18- 

 2.29); anterior margin shallowly, singly emarginate; lateral margin 

 weakly sinuate opposite ends of transverse impression; latter sub- 

 median, sharply impressed across full width, marked by entire row of 

 very closely set large punctures ; surf ace with several scattered, minute 

 punctures and a row of coarser ones on anterior lobe paralleling anterior 

 emargination, and several coarse ones discally on posterior lobe. 



Scutellum: Longer than wide, 1.52(1.49-1.56) : 1.26(1.25-1.28); dis- 

 cally polished, with scattered minute punctures but no large ones. 



Hemelytron: Clavus and corium feebly alutaceous; clavus with one 

 longitudinal row of coarse punctures; mesocorium obsoletely punc- 

 tured except for one row of close-set distinct punctures paralleling 

 claval suture; exocorium without distinct punctures; costa without 

 setigerous punctures; membranal suture weakly sinuate, lateral 



