26 INTKODUCTION. 



most nearly related groups., and the apparent size of the scutellum 

 changes with the position of the prothorax. This feature, how- 

 ever, is absent in the Trichiixi and Valgixi and in a few of the 

 remarkable horned Cetoxiixi. Another peculiarity of the Sub- 

 family is the pigmentation of the wings, the terminal part and 

 often the whole being coloured a deep red-brown or blue-black. 

 This is very unusual in beetles, although often found in insects in 

 Mhich the wings ai'e always exposed. 



The front coxa^ do not spread out in a transverse direction, as in 

 the Dynastix.t:, &c., but are inserted vertically, very prominent 

 and in close contact, and the presternum is not elevated behind 

 them. The middle coxse are transverse and level with the meta- 

 sternum, the front of which projects between them and often in 

 front of them, sometimes forming a long pointed or truncated 

 process. The end of tlie process consists of an elevated part of 

 the mesosternum united to the metasternum, but the line of 

 junction is not always traceable. The hind coxie are large, meeting, 

 except in the small species forming the Valgini, and generally 

 prominent at the sides of the body and visible from above. The 

 femora are simple and differ little, although those of the hind legs 

 are thickened or arched in the males of a few forms. The front 

 tibiae are generally toothed externally, at least in the female, and 

 the teeth are never more than three in number except in the 

 Valgini, most of which ha^•e five. The posterior tibiaj have often 

 an internal fringe of hairs and an external .spine near the middle. 

 The tarsi consist of five simple joints, except in certain 

 Ckemastochilini, which, living in the nests of Ants or Termites, 

 have become entirely abnormal in many points of their structure, 

 like many other insects leading the same peculiar life. The claws 

 are always simple and immovable, with rare exceptions in the front 

 claws of the males of certain African forms. 



The mouth is adapted for dealing ouly with soft or liquid food, 

 except in the Cbemastociiilini, which have the mandibles strong 

 and sharp although small. The labrum is reduced to little more 

 than a vestige, forming two membranous lobes entirely concealed 

 in the roof of the mouth. The maudibles, except those of the 

 Cremastociiilini, are thin and incapable of biting, consisting of 

 a blunt flexible rod with a membranous internal fringe at the base. 

 The maxillaj are well-developed, strong and generally toothed. 

 In typical Cetoniin.e they are covered with long hairs, which form 

 terminal tufts, often visible externally and apparently the chief 

 means of collecting the sweet juices upon which the insects feed. 

 The mentum is very chitinous, without a distinct ligula, and 

 generally bears long stiif hairs. JJoth maxillary and labial palpi 

 are 3-jointed and slender. In the Cremastochilixi the mentum 

 is dilated and forms a kind of operculum, coinciding with the 

 clypeus and shutting in completely all the other organs of the 

 mouth. 



The eyes are large, prominent and very finely facetted, and the 

 antennai consist of ten joints, the last three forming the club, and 

 varying very little. The basal joint is larger than the rest, and in 



