LAMELLICOBXIA. 11 



The front part of the head forms a small transverse clypeus, to 

 which is articulated the flap-like labrum which lies upon the 

 bases of the mandibles. These are strong and exposed. The 

 maxillae are fleshy, but generally bear strong horny teeth, and are 

 of two types, terminating in a single lobe in the Lucanid.t-; and 

 Pleurostict Scarab^idte and in two lobes in PassalidyI; and the 

 remainintr ScAEAii.MD.E. The labium is small and soft and carries 

 a pair of small two-jointed palpi. Of the three thoracic segments the 

 first alone has a pair of spiracles, and the first eight abdominal 

 segments have each a pair. The back is studded with minute 

 spines which produce a rough sensatiun to the touch and assist in 

 progression, and probably also render the grub a less agreeable 

 article of food. There is sometimes in addition a thin clothing of 

 stiif hairs. 



The leg consists of four joints, viz., a long basal joint, the coxa,, 

 a short trochanter, whicli is inmovably attached to the third, the 

 femur, and finally the tibio-tarsus, at the extremity of which is a 

 single claw. 



The larvae of many typical genera of Lameliicornia were very 

 carefully described and ficfured by Schiildte in Xaturhistorisk 

 Tidsskrift (3) ix. 1S74, and other descriptions, togetlier with a 

 useful tabular statement, were published in 1875 by Perris (Ann. 

 Soc. Linn, de Ijyon, vol. xxii.). 



I'ocal Organs. 



Lamellicorn beetles are remarkable for the variety of stridulat- 

 ing organs to be found amongst them and still more lor the 

 occurrence of these structures in the larvae — a phenomenon which, 

 so far as is known, is unique. They appear to be much more 

 general in the larvae than in the perfect insects, although fairly 

 frequent in the latter, and when present in both stages it is always 

 in entirely different parts of the body. 



Although aft'ecting a great variety of positions the organs are 

 always of the same general type. A modification is prochiced of 

 two parts of the body between which friction occurs in the 

 ordinary movements of the insect and one of the modified surfaces 

 bears minute and closely-ranged ridges or prominences of very 

 hard chitiii, capable of vibrating and so producing a shrill, more or 

 less musical, note. They have been described in some detail in 

 the Transactions of the Entomological JSocielv of London, 1904 

 (p. 709). 



In larvae of CETOxiixji, Dynastin.t: and Rutelinj: , an oval area 

 is found upon the lower face of each mandible which when 

 magnified is seen to consist of a number of regular sharp ridges 

 placed close togetlier and crossing the area transversely. Upon 

 the upper surface of each maxilla, near the base, in a position 

 corresponding to tlie ridged plate upon the mandible, is a row of 

 sharp horny hooks, and these, by movements of the ja\^s, pluck the 

 mandibular chords or ridges and so produce ; faint high-pitched 

 note. In some other groups of Scabab.eid-i: (Melolonthin.'e and 



