450 BULLETIN 18 2, UNITED STATES NATIONAL MUSEUM 



thopygus (Nordmann) (designated here) ; of Heteropygus^ Lampro- 

 pygus {Heteropygus) giganteus Bernhauer (monobasic).^" 



Diagnosis. — Head not densely nmbilicately punctate, margined be- 

 neath the eyes; antennae widely separated at anterior margin of head, 

 outer segments densely pubescent from the fourth joint; labrum bi- 

 lobed ; i^alpi slender, fourth segment of maxillary longer than third, 

 labial similar to maxillary; gular sutures becoming very approximate 

 posteriorly; pronotum with lateral margin double, upper line not 

 extending around anterior angle and never united with lower; ante- 

 rior coxal cavities open behind, except for a large peritreme; front 

 coxae very large, exserted; posterior coxae contiguous, "triangular"; 

 first and second abdominal sternites absent ; intersegmental membranes 

 of abdomen marked with a pattern of irregular rounded sclerotized 

 areas arranged in longitudinal rows; femora not strongly spinose 

 beneath. 



Remarks. — This genus is to a certain extent given a new meaning by 

 the return to it of X. xanthopygus which is its true genotype. That 

 species is not before me at present, but pexus agrees with the published 

 conceptions of the genus and has been used (with X. cognatus Sharp) 

 in writing the diagnosis. 



This genus is distinguished from Philothalpus (and Xenopygus) by 

 the disappearance of the upper marginal pronotal line at the anterior 

 angles. This group of genera is badly in need of a thorough revision, 

 and when that is made the number of genera will probably be further 

 reduced. 



Nine West Indian examples of the genus have been seen. They 

 belong to the following single species : 



1. XANTHOPYGUS PEXUS (Motschulsky) 



Belonuchus pcfvus Motschulsky, 1858, p. 667. — Gemminger and Harold, 1868, 



p. 596. 

 Lampropygus pexus (Mot.schulsky) Bernhauer, 1906, p. 196. — Bernhal'er and 



Schubert, 1914, p. 407. — Lknq and Mutchler, 1914, p. 405. 



Description. — Black, apex of abdomen ruf otestaceous. Head nearly 

 one-third wider than long; eyes not prominent, occupying not over 

 one-half the sides ; the posterior angles marked by a ridge ; with very 

 scattered punctures except along middle, more dense along base, 

 feebly umbilicate; with very fine and irregular strigulose ground 

 sculpture. Pronotmn scarcely wider than long, widest at anterior 



*'The above designation of L. xanthopygus as genotype of Lnmpropuguft may seem to l^e 

 arliitrnry but is based on what I believe to be sounil reasoiiinsr. In proposing the name 

 Lampropygus, Sharp was in error because he included the previously established type of 

 Xanthopygus. His name will therefore always be at least in part synonymous with 

 Xanthopygus. Less confusion will result if the namt Lampropygus is definitely and irre- 

 vocably rejected in this manner, and, if tlie other species included does prove to be distinct 

 geuorically, a new name can be proposed tor it tliat will have a more definite application 

 and will not involve a change in the conceF<t of an establisliod genus. 



