LAMELLICORNS 



191 



the form of the antennae is not so widely different from that of 

 other Coleoptera. The larvae live on decaying vegetable matter, 

 roots or dung. They 

 have three pairs of 

 legs, and are thick 

 clumsy grubs with 

 curved bodies, the 

 last two segments 

 being of larger size 

 than usual. Many of 

 them possess organs 

 of stridulation, and 

 the structure of their 

 spiracles is very 

 peculiar, each one 

 being more or less 

 completely sur- 

 rounded by a chitin- 

 ous plate. The 

 spiracles usually form 

 a system entirely 

 closed, except at the 

 moment when the 

 skin is shed and the tracheal exuviae are detached. Meinert ^ 

 considers these spiracles to be organs of hearing. The life of the 

 larvae is passed underground or in the decaying wood on which 

 the Insect feeds. 



Most of the members of this series are remarkable on account 

 of the great concentration of the nerve-centres. This is extreme 

 in Rhizotrogus, where there are only two great ganglia, viz. the 

 supra-oesophageal and a great ganglion situate in the thorax, 

 and consisting of the conjoined i nfra-oesophageal, thoracic, and 

 abdominal ganglia. According to Brandt '" there are several 

 distinct forms of concentration in the series ; the Lucanidae only 

 participate in it to the extent that the perfect Insects exhibit 

 fewer ganglia than the larvae ; the latter possess two cephalic, 

 three thoracic, and eight abdominal ganglia, while the perfect 

 Insect has the abdominal ganglia reduced in number to six, and 



^ Danskc Sclsl: Skr. (6), viii. No. 1, 1895. 

 - Home Soc. cut. Boss. xiv. 1879, p. 15. 



Fig. 85. — Antenuae of Lauiellicorus. 1, Xdcus inter- 



ruptus ; 2, Lucaniis cervus i; 3, Fhanaeits sj^len- 



didulus 9 ; 4, Phileurus didymus 9 ; 5, PolyphylUi 

 /alio i. 



