4 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 76 



In all the species the scales on certain regions of the body are 

 modified by a more or less complete splitting process, resulting in 

 what are here termed plumose scales,^ Roughly speaking, three 

 types, or three stages of development, are illustrated within the genus; 

 first, a weakly plumose type, in which only the margin of the scale is 

 affected, giving it a slightly frayed appearance; second, a form in 

 which the normally rounded scale is split entirely to base into a 

 number of filaments; third, a narrow, elongate type which consists 

 of a central stalk from which rise numerous short branches. The 

 most highly developed types have been found on the abdomen of 

 several western species, while, in the eastern species, feebly plumose 

 scales are present on the head, and front and rear coxae, in addition 

 to a few on third, fourth, and fifth, and along rear margins of first and 

 second abdominal segments. In Mesagroicus, the plumose scales 

 appear in different stages of development on different parts of the 

 body of the same individual; they are always smaller than the entire 

 scales of the same specimen; they are not present on the dorsum of 

 prothorax or elytra; and the deeply split forms occur in connection 

 with two other features, namely, a more pronounced striation of the 

 elytral scales, and a finer, denser abdominal punctation. With the 

 possible exception of Trigonoscuta Motschulsky and Plenaschopsis 

 Blaisdell, none of the many North American Otiorhynchid genera 

 examined for this character possess plumose scales approaching the 

 high development shown in several species of Mesagroicus. 



What little is known of the biologies indicates that the genus is one 

 of general feeders and that some of the species may occasionally 

 become injurious to cultivated plants. The original set of Tierricki 

 Pierce was found damaging young cotton plants, while another 

 specimen of the same species was collected on cowpea. Several 

 specimens of minor are labeled as *' injuring potatoes "; while Jiispidus 

 was found "feeding on sugar beet" in California. 



In the key, minor and ohlongus are separated principally by a differ- 

 ence in the length of the scape, measured across eye. The scape, in its 

 position of rest, lies along the lower margin of the eye, and it is neces- 

 sary, therefore, to carefully pull or push it up, by means of a needle, 

 until it bisects the eye, in order to accurately determine the relations 

 of the two. This operation is possible without relaxation of the 

 specimen and with little danger of breakage. It is needless to add 

 that the scape, when in the extended position, can not be rotated back 

 to the head without relaxation. 



The 10 species and subspecies are divisible into three groups as 

 follows : 



2 Scales of this or a similar nature, which are present on many weevils, have been variously called 

 feathery, plumose, plumate, split, multifurcate, or shaggy by different writers. 



