GREEN OR LIVING VEGETABLE MATTER. 83 



a convenient test of the accuracy of a method of classifi- 

 cation, compose nevertheless a field of discovery well worth 

 the trouble of exploring. With the Melolonthida this dif- 

 ference is principally observable in the form of the cly- 

 peus and the antennas, which often undergo modifications 

 which vary in the sexes. In the Anoplognathida, on the 

 other hand, the antenna? cannot be considered as present- 

 ing the most obvious distinction between the appearance 

 of the sexes, though this may still chiefly consist in some 

 organ or process of the head. Thus in the first division 

 of the genus Anoplognathus, the clypeusof one sex isporrect 

 and subquadrate, with the anterior margin reflexed, sub- 

 truncated and wider than at the base ; while in the other 

 sex the clypeus, though its anterior margin be still reflexed, 

 forms a sort of semicircle attached by the suture to the 

 frons. In the second division, that is, in Dr. Leach's pro- 

 posed genus Repsimus, this sort of distinction becomes 

 less apparent, and is replaced by a difference in the size of 

 the posterior tibiae. In others of the AnoplognathidcB, as 

 the genus Gemotes of Mr. Kirby, the male is distinguished 

 by a stiff pencil of hairs affixed to the mentum, which is 

 thus in a manner bearded, while the anterior tarsi are di- 

 lated. This dilatation of the anterior tarsi is a character 

 not only wanting in the female of Geniates, but also in all 

 the other petalocerous insects which have come under my 

 inspection. 



If we may judge from the singularity of their structure, 

 the economy of these insects must be very remarkable. 

 Their thick robust feet form indeed so great a contrast to 

 those of the Thalerophagous Petalocera in general, that we 

 are led to conjecture a proportionate difference in their man- 

 ner of living. The Anoplognathida are, however, evidently 



G 2 



