24 PROCEEDINGS OF .THE NATIONAL MUSEUM vol. 105 1 



when studying the collections of Delauney from the French West 

 Indies and referred to the flatid genus Carthaea Stal, Thhteen years 

 later Uhler described the new species musca from St. Vincent and 

 erected the genus Cheiloceps for its reception. According to the exist- 

 ing characterization of Thionia Stal, Cheiloceps must be placed in 

 synonymy, but its original species and other West Indian species, 

 described below, differ strikingly from typical Thionia (e. g., T. lon- 

 gipennis Spinola) in the structure of the ovipositor as well as in bodily 

 proportions. There is a little evidence, derived partly from examina- 

 tion of a few undescribed Thionia from Central America and partly 

 from comparison of the shape of the ovipositor in various species of the 

 genus Colpoptera, that with sufficient material it will prove possible to 

 find a series of intergrading forms. Nevertheless, the West Indian 

 species form a distinct and natm-al group within the genus, and the 

 name Cheiloceps may usefully be preserved at subgeneric level for this 

 group. 



These are the only Lesser Antillean issids described, but recently 

 material of a small Acanalonia from Antigua, B. W. I., has been 

 referred by Caldwell {in Caldwell and Martorell, Puerto Rico Univ. 

 Journ. Agr., 1950, vol. 34, No. 2, p. 268, 1951) to a species described 

 from the Greater Antilles. Apart from this particular disposition, it 

 is relevant to refer to the study of Puerto Rican Issidae in the paper 

 cited, as the data there presented shed much light on the source from 

 which the Lesser Antillean Issidae have been derived. 



It appears to be generally true that wherever related faunas can be 

 closely compared, members of the Issidae are among the foremost of 

 those forms which exhibit the greatest degree of morphological differ- 

 ence, and are sensitive indicators of degree of population divergence. 

 In the Lesser Antillean species the differences are most obvious, and 

 sometimes only appreciable, in the genitalia of the male. 



One species, Colpoptera maculifrons Muir, is clearly polytypic. Two 

 of the processes of the male genitalia vary in their relative lengths to 

 an unusually large extent even within populations from a single 

 locality, and this degree of variation is not appreciably exceeded by 

 that between populations from two or more different localities, even 

 on different islands. Interisland differences, however, which are con- 

 stant within any one population, appear m the shape of the distal part 

 of the tegmina and in coloration, and it is these, rather than genitalic 

 structure, that provide reliable characters for the recognition of any 

 subspecies. 



Of the other Lesser Antillean members of the genus Colpoptera, one, 

 described below as new, is very close to C. nemonticolens Caldwell. 

 The genitalic differences in both sexes are sufficiently large to make it 



