COIiEOPTERA. 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 elytra over finely wrinkled surfaces, which in 

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

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

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

 on the surface of the elytra. 



The nervous system is subject to great Aariation in tlie Cole- 

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

 ses, as in the Lamellicorns, Curculionidm and Scolytidoi, 

 where the first mass corresponds to the prothoracic ganglia, 

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

 usually 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 system. In the Cistel- 

 idce, (Edevieridce and Cerambycidce, 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 alwaj^s distinct in 

 the larva state. 



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

 cies, going directl}^, without many convolutions to the anus, 

 but in the vegetable feeders it is very long and greatly con- 

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

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

 ary tubes are either four or six in number. 



"The phosphorescent organs of the Lampyridce and cer- 

 tain Elateridie consist of a mass of spherical cells, filled 

 with a finety granular substance and surrounded by numer- 

 ous tracheau branches. This substance which, b}' daylight, 

 appears of a yellow, sulphur-like aspect, fills in the Lcivi- 

 Ijyridce, a portion of the abdominal cavity, and shines on the 

 ventral surface through the last abdominal segments, which are 

 covered with a ver}'^ thin skin ; while with the Elateridce , 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 undoubtedl}' the 



