148 PROCEEDINGS OF THE NATIONAL MUSEUM vol.87 



more or less pubescent. As in Galerucella, there are often traces of 

 one or two raised lines on the inner half of the elytra, parallel to the 

 suture and particularly evident in the basal half. The epipleura do 

 not extend to the apex. Beneath, the body is finely pubescent. The 

 prostemum disappears between the anterior coxae, and the precoxal 

 cavities are open. Usually the tip of the abdomen appears truncate 

 in the male, owing to the pygidium coming down and meetmg the 

 concave last visible sternite much like the flap of an envelope. In 

 the female the pygidium is less in evidence, and the tip of the abdomen 

 is more oval. In some species, as in the sordida group, and also in 

 M. hatisii, this development of the pygidium in the male is not so 

 striking and the two sexes are not easily differentiated by it. 

 The legs are without spurs or teeth and the tibiae are glabrous on the 

 outer edge. The claws are toothed in the male, but usually simple in 

 the female. 



In one group of species, consisting of sordida and two closely related 

 species, the claws are toothed in both sexes. These species are also 

 peculiar in having a short, wide prothorax, over twdce as wide as long. 

 Furthermore, the abdomen of the male in most specimens is not so 

 truncate as in the other species. These peculiarities make the group 

 somewhat intermediate in character between the genera Monoxia 

 and Galerucella. Besides these three species, another species, described 

 here as Monoxia schizonycha, has the claws toothed in both sexes, but 

 in other characters it is similar to M. conspnta and others in which the 

 claws are dimorphous. The abdomen of the male of M. schizonycha, 

 also, is truncate, as in the majority of the species. 



The aedeagus of all the species is a shnple bowed structure. In some 

 it is short, broad, and with a well-rounded tip ; in others, long, narrow, 

 and tapering acutely to the tip. Frequently the aedeagus varies 

 somewhat in specimens of a species from different localities. The 

 general structure and shape are the same, but sometimes there is 

 considerable diversity in the length or in the shape of the tip or in the 

 position of the dorsal opening. This is most marked in species having 

 a wide range (as in sordida, which occurs in eastern Texas and Western 

 United States) and has led me to doubt if the eastern colonies are the 

 same as the western. In such cases more biological work is necessary 

 before any conclusion can be reached. Eveu in a series from a single 

 locality there is considerable variation, and in some cases, among 

 groups of closely related species, the aedeagus does not afford good 

 distinctive characters. 



The color and markings vary so as to be exceedingly misleading. In 

 almost every species is found a gradation from pale forms, often without 

 any marldngs whatever, through various stages to heavily marked. 

 In fact, it is rather rare to find two specimens of a species marked 



