CETOXiiisriE. 25 



Structure. 



The exterior is very bard and chitinous, fi-eqiienth' covered witlv 

 a peculiar bloom, like that of a ripe plum, and decorated with 

 spots or patches of white or yellow consisting of a powdery sub- 

 stance which appeal's to be of a similar nature to hairs or scales 

 and usually occupies slight depressions in the integument. In 

 rare cases this substance has a silvery, golden or opalescent lustre, 

 but it is generally quite dull. In the small species forming the 

 section Valgini this type of decoration is not found, but the body 

 is more or less covered with scales of different colours, by which 

 patterns are produced. 



As in the Dynastinj^, Euteli>^e and INIeloloxthix.e, the 

 abdomen is composed of six segments ventrally, the last dorsal one 

 is large and exposed, and the posterior spiracles are situated in 

 the chitinous dorsal part of the ventral segments and not in the 

 flexible membrane connecting the ventral and dorsal parts of the 

 abdomen. A peculiarity in the structure of the spiracles is found 

 in the Valgixi and a few members of other sections, the last pair 

 of spiracles, and sometimes in a less degree the one or two pairs 

 immediately preceding, being placed at the end of prominent 

 horny tubercles. 



The front of the head, or clypeus, is always well developed, 

 forming as a rule a broad shovel- like instrument and apt, 

 occasionally in both sexes, but more often in the male alone, to 

 give rise to horns of various forms and sometimes considerable size. 

 In a few cases the prothorax of the male bears a similar 

 armature. 



The prothorax is typically fitted very closely to the hinder part 

 of the body, generally having eitlier an excision in front of the 

 scutellum or a prolongation by which the latter is partly or entirely 

 concealed. All the species are active fliers and, except in the 

 small section of the Teichiini, flight is accomphshed in a very 

 characteristic manner, with which is connected the most distinctive 

 features of their external anatomy. The elytra are not lifted high 

 and carried back to back in flight, according to the common manner 

 of beetles, but are only slightly raised and the wings are slipped 

 out beneath their lateral edges. The elytra accordingly only 

 wrap over the body near the shoulders and are more or less reduced 

 at the sides, sometimes becoming quite narrow and distinctly 

 exposing the lateral parts of the back. Together ^vith this com- 

 parative immobility of the elytron, has been produced a general 

 consolidation of the body and close co-adaptation of its parts. 

 The epimera of the mesosteruum are so developed as to fill the 

 angles" between the prothorax and the shoulders of the elytra and 

 the prothorax slides over the elytron and the mesothorax, so that 

 even when drawn forward it has not free play in all directions 

 but remains closely applied to the hind body. There is thus no 

 arresting ridge at the front of the elvtra and scutellum as in the 



