COLEOPTERA. 425 



number of abdominal segments is ten, no more than nine have 

 been traced in the Coleoptera. 



A few genera are capable of producing sounds by rubbing 

 the limbs or elj^tra over finel}^ wrinkled surfaces, which in 

 Trox are situated on the side of the basal segments of the ab- 

 domen, and in Strategus on the tergum of the penultimate seg- 

 ment of the abdomen, while such a surface is found in Ligyrus 

 on the surface of the el34ra. 



The nervous system is subject to great variation in the Cole- 

 optera. The ganglia may be fused into three principal mas- 

 ses, as in the Lamellicorns, Curculionidui and Scolytidcej 

 where the first mass corresponds to the prothoracic ganglia, 

 the second and larger to the second and third thoracic ganglia, 

 usuall3^ separated in the other suborders, while the third oblong 

 mass represents the whole number of abdominal ganglia, from 

 which radiate the nerves which are distributed to the muscles 

 of the abdomen and the reproductive s^^stem. In the Cistel- 

 idce, (Edemeridce and Ceravibycidce, the abdominal por- 

 tion of the nervous cord occupies the whole body, and there 

 are five ganglia in the abdomen. These two tj'pes of the ner- 

 vous cord sometimes run into each, but are always distinct in 

 the larva state. 



The alimentary canal is very simple in the flesh-eating spe- 

 cies, going directlv, without many convolutions to the anus, 

 but in the vegetable feeders it is ver^' long and greatl}^ con- 

 voluted. The gizzard is oval in shape, its internal folds being 

 armed with hooks. There are two salivary glands. The urin- 

 ar}^ tubes are either four or six in number. 



" The phosphorescent organs of the Lampyrida' and cer- 

 tain ElateridcB consist of a mass of spherical cells, tilled 

 with a finely granular substance and surrounded by numer- 

 ous trachean branches. This substance which, by daylight, 

 appears of a j-ellow, sulphur-like aspect, fills in the Lam" 

 jjyridce, a portion of the abdominal cavit}', and shines on the 

 ventral surface through the last abdominal segments, which are 

 covered with a very thin skin ; while with tlie E I ater idte , the 

 illumination occurs through two transparent spots, situated on 

 the dorsal surface of the prothorax. The light produced by 

 these organs, so remarkably rich in tracheie, is undoubtedly the 



