INTRODUCTION 



LUCANIDiE and PASSALIDiE 



The LucANiD.^ unci Passalidje form, with tho .Scarabjeidje, 

 tlie immense Suborder (or Sujierfamil}') Lamelheornia. Being 

 relatively small groups which number together only a fraction 

 of the number of species comprised in the Scarab^id^, it is 

 natural to treat them togetlier, but it must not therefore 

 be inferred that they are actually related very closely. 

 Although at one time it was customary to unite them in a 

 separate group (called the Pectinicornia) they are more 

 naturally included in the great Lamellicorn group. 



In many respects the two families differ greatl}' in botli 

 larval and adult stages, the contrast being very great in tlie 

 larvae. Those of the Lucanid^ have the same general form 

 as those of other Lamellicorns, and like these normally lie 

 upon the side, the body curved like the letter C, with the three 

 pairs of legs lying close together inside the curve. Passalid 

 larva> have the body comparatively straight, there arc only 

 two jiairs of functional legs and tliey are widely separated. 

 The third pair are represented by vestiges so minute that they 

 are almost invisible without magnification. They lie clo.se 

 behind the second pair, have lost all trace of their original 

 form as organs of locomotion and apimrently serve only to 

 scrape microscopic ridges upon the surface beneath them, the 

 friction causing a scjueaking noise. Lucanid larvae also squeak 

 by means of a special apparatus upon the two hinder pairs 

 of legs but all the legs are fully developed, as in other 

 Lamelheornia. 



In the adult beetles there is a very strong contrast between 

 the uniformity of the Pas.salid.^ and the variety of the 

 Lucanid^. The former are shining black insects, narrow- 

 bodied, parallel-sided, with short legs and aiitennje. The 

 latter ma}' be black and shining but they are often brown, red 

 or yellow ; they may dis])lay boldly contrasted combinations 

 of light and dark colours or even (though not in India) tlie 

 most vivid metallic green, golden or iiery red. They may be 

 narrow but are sometimes extremely broad. The legs and 

 antennae may be short liut are often very long. In structural 

 details the two groups have little in common except such as 

 are shared with nearly all Lamellicoriiia. Tn the Passaliu^e 

 the connection between the front and hind l)ody is very 



tMttiim 



