FAMILIES PASSALIDAE AND LUCANIDAE 69 



in July. It is plentiful in this locality, between 4,500 ft. and 6,000 ft. The 

 beetle was never taken in sound timber. It would seem probable that the 

 insect matures at irregular intervals in the spring and summer months. It 

 is to be found in the larval stage in the autumn and winter, making irre- 

 gular ramifying tunnels in the soft, decaying sapwood, beneath the bark of 

 standing or fallen rotting stems. 



It has also been reported from Jaunsar, in the North-west Himalaya, 

 at 5,000 ft. elevation, at the end of April. 



ACERAIUS. 



Aceraius hirsutus, Knw. 



Reference. — Knw. Nov. Zool. v, p. 343 (1898). 



Habitat. — Evergreen Forests, Bhorelli River, Darrang, Assam. 

 Trees Attacked. — Tcrminalia, Shorea, Lagcrstromia, Schima. Ever- 

 green Forests, Darrang, Assam. 



Beetle. — Large, shining, black ; sides of thorax and basal half of elytra densely hirsute. 



Head large, vertex with sharp irregular raised lines and points, the depressions hirsute ; eyes 



large and prominent ; mandibles large, toothed. Prothorax wider 



Description. than long, convex, smooth and shining ; a more or less circular 



pitted depression on lateral margin just below the centre. Elytra 



constricted apically, shining, striate-punctate, striae very hne. Under-surf;\ce black, duller. 



Length, 31 mm. to 38 mm. 



I took numbers of this beetle, some large, others of small size, in the 



rotting wood of fallen decaying trees of the genera 



Life History. Terminalia, Shorea, Lagerstromia, and ScJiiiua, in the 



Evergreen Forests, near Bhorelli River, about the middle 



of April igo6. The beetles were only found in decaying trees, and were all 



either in the semi-pupal or mature state, I know nothing further on the life 



history of this insect. 



Family LUCANIDAE. 



{Stag Beetles.) 



The Stag Beetles are easily recognizable owing to the great development 

 of the mandibles of the males into prolongations having some resemblance to 

 a stag's antlers (fig. 37). The females do not possess these exaggerated man- 

 dibular structures, their short thick black biting jaws being of the normal size. 

 The beetles are usually large bulky insects, the males being larger than the 

 females. The enlarged end joints of the antennae are characteristic of the 

 family, since they are fixed into a straight cone-shaped knob instead of 

 forming movable plates. The visible segments of the abdomen are five in 

 number. 



