INTRODUCTION. O 



limbs are seen to have the sliai)c of a tiny hand or paw with 

 five or six projections very sharply pointed at the end. The 

 area at the base of tlve [uecediiig leg, upon which this curious 

 limb lies, is darker than the surroundhig surface and, closely 

 examined, is found to bear a number of very line ridges, 

 capable of vibrating when plucked by the claws of the httle 

 " paM." To human ears the sound so j)roduced, as it has 

 been described by Ohaus, is soft but easily audible at a short 

 distance. The four normal legs are rather long and slender. 



A small distinctive feature of the Passalid larva in its early 

 stage is a pair of hatcliing-spines or egg-bursters. These 

 are sharp projections found one on each side of the upper 

 surface of the mctathorax. They serve to break the egg-shell 

 and are shed when the first skm is cast. 



The distinctive features of a number of Indian species of 

 l*ASSALii)^E have been described by Dr. Gravely in the paper 

 mentioned above. The larva; of the AuLACOCYCLiNiE and of 

 Leptaulax can be distinguished, according to him, from those 

 of the remaining Indian genera by the form of the terminal 

 lobe of the last ventral segment, wliich is deeply cleft, wliilst 

 in the rest it is entire. 



The organs of the mouth do not greatly differ in Lucanid and 

 Passalid larvai, but Gardner (Indian Forest Records, vol. i, 

 1935, p. 2) has recorded that the grinding apparatus of the 

 mouth in the latter is reduced, as compared with that of the 

 Lucanid larva, and says " the difference would be difficult 

 to explain were it not for the observations of Ohaus, who 

 found that . . . the parent beetles attend their progeny 

 throughout their larval period and present them with already 

 masticated food." 



The larval period appears to be much shorter and the adult 

 life longer than in the Lucanid^. The eggs do not all mature 

 together, but seem to be laid at intervals during several months. 

 In the case of Passalns cornutits eggs, larva; and pui)ai were 

 all found together and the comi^lete metamorphosis appears 

 to be accomi)lished in the course of a single summer. 



Another LamcUicorn group in which stridulation by the 

 larvai is performed in a similar way to that adopted by the 

 LucANiD.E and PASSALiDyE is that of the GEOTRuno^. In 

 that group tiic larval legs are to some extent intermediate 

 in their stage of development between the conditions found 

 in our two families. The tliird pair are specially adai)ted 

 for scraping the bases of the second pair and are reduced m 

 size, but without the v(;ry great degree of specialization found 

 in the Passalid^. Although the short, compact-bodied adult 

 GEOTRUPiD-^.have little resemblance to either Lucanid^ or 

 Passalid^e, there are many reasons for regarding them as a 

 primitive group related to the ancestors of both. Larval 



