656 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 117 



Leng (1918) further introduced Monachulus (now in synonymy) also 

 to replace preoccupied Monachiis Chevi'olat. 



The first known North American species, Cryptocephalus saponatus, 

 was described by Fabricius in 1801. Nearly forty years later Perbosc 

 (1839) described Cryptocephalus guerini. Monachiis ater, M. affinis, 

 and M. auritus were described by Haldeman (1849). Monachus semi- 

 nulum was described by Suffrian (1858) and Monachus thoracica by 

 Crotch (1873). The remaining species, described in the twentieth 

 century, are: Monachus mexicanus Jacoby (1908); Monachulus viri- 

 danus Fall (1927); and Monachulus opacicollis Schaeffer (1933). A 

 key to the species then known for the genus in America north of Mex- 

 ico was published in 1880 by LeConte. Wickham (1895) used part of 

 this key in his paper on the tribe CryptocephaUni in his series on 

 Canadian Coleoptera. Blatchley (1910) also presented a key, but 

 only to the species occurring in Indiana. In the present study, five 

 distinct species are recognized in Nearctic America north of Mexico. 

 Four of the above specific names are here synonymized and two junior 

 sjTionyms re-established as senior. 



Origin and distribution: The genus Lexiphanes occurs only in the 

 Western Hemisphere. Comparatively speaking. North America is 

 poorly represented in the genus. Blackwelder (1946) lists twenty- 

 three species from Central America, whereas ninety-three were re- 

 corded for South America. Assuming no reduction of range, northern 

 South America appears to be the center of distribution and the prob- 

 able center of generic origin. Two faunal regions include the five 

 North American species : the eastern United States as far west as the 

 plains, and the southwestern United States, including parts of Texas, 

 Colorado, New Mexico, and Arizona. The western species represent 

 the northernmost distributions of a Central American group. The 

 three eastern species are possibly completely disjunct from their 

 Central American relatives. 



Methods and terminology : The abdomen was removed and cleared 

 overnight in 10 percent solution of sodium hydroxide. The genitalia 

 were removed from the abdomen, washed in distilled water, examined, 

 and stored in glycerine in micro-vials attached to the insect pin. The 

 empty abdomen was washed and mounted on a paper point beneath 

 the insect. The aedeagi were measured from the apical tip to the 

 anterior end of the internal sac. The total length of the beetle was 

 taken from the front of the pronotum to the apex of the elytra, while 

 the width was measured at the widest part (slightly behind the humeral 

 calli) . 



A study of this kind requires assemblage of a large amount of 

 material. The author has been fortunate enough to examine large 

 series of specimens through loans from various institutions. For the 



