478 PROCEEDINGS OF THE NATIONAL MUSEUM vol. in 



Distribution. — The range of the nommal subgenus occupies the 

 southern part of the range of the genus, overlapping the range of 

 subgenus Homaloporus to the north for a short distance in Guatemala 

 and southern Mexico. 



Discussion. — The problems encountered in this subgenus were 

 somewhat different from those found in most other parts of the 

 family. The males of all forms were rather easily separated with the 

 aid of secondary sexual characters, but not all the females have, as 

 yet, proven decipherable. Therefore, as indicated in the key to 

 species, females of certain species cannot yet be properly separated 

 from their congeners. This situation results from the great varia- 

 bility of external features in the females which either prevent estab- 

 lishment of reasonable limits to the species as indicated by the males, 

 or results in the separation of a disproportionate and unbelievable 

 number of forms. Therefore, until later studies of the internal 

 genitalia are made, the author deems it best to treat only such females 

 as lend themselves to ready association with males through possession 

 of some outstanding common character. 



Key to the species of Pangaeus (Pangaeus) 



1. Posterior tibia with spines of postero ventral margin conspicuously longer, 



thinner, and sharper than those on dorsal margin (fig. 159) ; head trans- 

 versely convex, basal half or more of jugum with several distinct, coarse, 



transverse rugae 2 



Posterior tibiae with spines equally developed on all margins; head flattened, 

 jugum with broad, shallow, longitudinal impression medially 5 



2. Jugum with a complete, submarginal row of setigerous punctures which give 



rise to a series of pegs and hairs 3 



Jugum without a complete row of submarginal setigerous punctures, those 

 which are present give rise to hairs but not pegs 4 



3. Mesocorium with numerous moderate but distinct punctures over entire 



surface semibrunneus, new species (p. 502) 



Mesocorium virtually impunctate subtiljus (Signoret) (p. 507) 



4. Costa with ten or more setigerous punctures; tibiae and femora concolorous. 



pluripunctatus, new species (p. 479) 



Costa with five or less setigerous punctures; basal third or more of hind 



tibia and apex of femur yellow, distinctly lighter than greater part of 



femur xanthopus Signoret (p. 481) 



5. Jugum with four setigerous punctures submarginally (fig. 47) 6 



Jugum with one or two submarginal setigerous punctures 9 



6. Anterior pronotal lobe laterally with broad patch of numerous distinct, 



moderately coarse punctures 7 



Anterior pronotal lobe impunctate or with less than half dozen distinct 

 punctures 8 



7. Pronotum with subapical impressed line and midline of anterior lobe dis- 



tinctly punctate (fig. 74) punctinotum, new species (p. 495) 



Pronotum with subapical impressed line and midline of anterior lobe im- 

 punctate; calli posteriorly with numerous small rugae (fig. 73). 



rugonotum, new species (p. 501) 



