596 PROCEEDINGS OF THE NATIONAL MUSEUM vol. iii 



the lack of coarse crenulations on the posterior margin of the meso- 

 pleuron and the mesopleural evaporatorium which is usually entire 

 and reaches uninterrupted to the posterior margin of the segment. 



Description. — Agreeing with the generic description with the fol- 

 lowing important modifications: 



Head: Jugum with complete, fine, marginal carina dorsally, usually 

 with two or more submarginal setigerous punctures; labial length 

 variable from between middle coxae to base of sternite II. 



Mesopleuron : Posterior margin usually with fine crenulations or 

 none; evaporatorium extending into posterolateral angle of segment, 

 usually attaining lateral margin. 



Metapleuron : Lateral margin of evaporatorium usually straight 

 or nearly so (deeply concave only in fusus) ; apex of peritreme not 

 (except in fusus) fusing with surrounding cuticula. 



Legs: Posterior tibia of both sexes without angulation near base 

 of posteroventral margin, femora not tuberculate ventrally on apical 

 fourth. 



Type of subgenus. — Same as for type of genus. 



Distribution. — From southwestern United States south through 

 Central America and the West Indies to southern South America. 



Discussion. — Comments on the definition and relationships of this 

 taxon will be found in the generic discussion. 



Several of the new species described in the present study appear to 

 be somewhat intermediate between this subgenus and the subgenus 

 Dallasiellus (Pseudopangaeus) . Notes on these will be given at 

 appropriate places in the text. 



Key to species of subgenus Dallasiellus (Dallasiellus) 



1. Dorsum of head coarsely and in large part rugosely punctate 2 



Dorsum of head not coarsely rugopunctate, either impunctate or with 



widely separated punctures 3 



2. Bucculae abruptly terminated posteriorly (as in fig. 23) ; corium and sternites 



not distinctly alutaceous puncticeps, new species (p. 622) 



Bucculae evanescent posteriorly; corium and sternites distinctly alutaceous. 



solitaria (Horvdth) (p. 624) 



3. Peritreme abruptly terminated apically (fig. 107); lateral margin of meta- 



pleural evaporatorium straight or gently concave 4 



Apex of peritreme not abruptly terminated, fusing with surrounding cuticula 

 (as in fig. 106) ; lateral margin of metapleural evaporatorium very deeply 

 concave (as in fig. 106) fusus, new species (p. 604) 



4. Mesopleural evaporatorium interrupted near or at posterior margin by trans- 



verse, polished band (fig. 108) 5 



Mesopleural evaporatorium not thus interrupted (fig. 107) 6 



