LONGICORNIA. 



183 



says that " so far the essential difference between the Tetramera, 

 of which the larvae feed upon wood, and those feeding upon 

 vegetable cellular tissues, has eluded observation. We can merely, 

 at present, observe that a slight approximation to it seems to be 

 made in the fact that in the CerambycidvE (here regarded as 

 including all the Loxgicornia) there is a tendency in the epimera 

 of the metathorax to extend to the sides of the ventral segments, 

 while in the Chrysomelidje the first ventral segment is prolonged 

 forwards at the sides to meet the metathorax, thus showing 

 probably a lower, though necessarily more recent type, which 

 could have existed only since the development of the higher 

 broad-leaved plants." 



According to Lameere (Ann. Soc. Ent. Belg. xliv, 1 900, p. 368) 

 the connection between the Chrysomelid^e and CerambycjevE is 

 not a close one. They have probably been evolved from different 

 ancestors, these being, most likely, primitive Clayicorxia ; he 

 therefore only provisionally adopts the series Piiytophaga, as 

 he is of opinion that the Lo:n t gicor]nta in the future will have to 

 be considered as a group distinct from the series altogether. It 

 is possible that he may be right when he regards Parandra as the 

 archaic type of the Longicorns, but we cannot agree with him 

 when he says that the study of the genus " shows that the 

 Cerambycie^e are only a special form of Clavicorns allied to 

 the TrogositidvE and Cucujidve." 



So far as is at present known, the Lo^gicortnia comprise about 

 12,000 or 13,000 species ; although those which have been 

 described are, perhaps, more numerous relatively than in any other 

 section of the order, owing to their striking appearance and colora- 

 tion, yet it is probable that only a half or a third of the existing 

 species have been discovered. The larvae differ considerably from 

 one another ; as a rule they are elongate fleshy grubs with nothing 

 remarkable about them, but occasionally the prothorax is much 

 widened, so as to suggest Butrestid.e rather than Loxgioor^ta. 

 It is probable that the group may, in the future, be divided on 

 the characters of the legs or absence of the legs ; in many cases 

 short legs are present, but in the majority they are absent, and 

 a good many instances occur in which the body has on its surface 

 swellings above and beneath, which are probably intended to 

 assist locomotion in the galleries in wood in which they live ; 

 these galleries are sometimes occupied by the same larvoo for 

 several years. 



The Longicorista are well known for their cryptic coloration 

 (protective resemblance to various objects), in fact, some of the 

 best instances are found among the members of this group ; 

 Desmophora, Batocera. Saperda, and Lamia are good instances, 

 but the Indian Xylorrliiza adusta, Wied., is still more striking, and 

 the best instance of all is afforded by the large African Petrognaiha 

 gigas, F. The upper surface of this fine insect is like dead velvety 

 moss, and the antennas are uneven and exactly like dry wood 

 tendrils. I have before this (Proc. Ent. Soc. Lond. 1901, p. xlv) 



