264 DT>'A8TI1<M. 



the cephalic horn and, measured from the tips to the base of the 

 thorax, considerably exceeds the elytra in length. The inner edge 

 of the front tibia is gently bisinuate and the outer edge armed 

 with three very sharp slender teeth, of which the two uppermost 

 are rather distant. 



In males of minor development (var. oromedon, F.) the tooth at 

 the upper edge of the cephalic horn disappears and the thoracic 

 horn does not extend as far as that of the head and is very feebly 

 bifurcated. 



In the smallest specimens the cephalic horn is extremely short 

 but distinctly bifid and the thoracic horn vanishes completely, 

 being represented only by a slight eminence. 



5 . This is generally rather darker in colour and the upper 

 surface is much more rugose. The head is very rugose, the 

 pronotum coarsely punctured, the punctures coalescing at the front 

 and sides, the scutellum thinly, and the elytra closely and 

 irregularly, punctured. The pygidium is finely rugose and the 

 abdomen irregularly punctured beneath. 



Lencjth* 25-50 mm.; breadth 13-28 mm. 



Bengal: Calcutta; Sikkim : Karsiang ; Assam: Shillong, 

 Sibsagar, Cachar ; Bombay ; Travancoee ; Cetlox. 



Thomson's types are in M. Bene Oberthiir's collection : the 

 location of the older types is uncertain. 



Males vary to a remarkable degree, not only in size and degree 

 of development of the horns, but also in the texture and fine 

 sculpture of the upper surface. Many so-called species have been 

 based upon the different phases of this sex, but none of them 

 appear to have at present justified themselves by sufficient evidence 

 of constancy or even local distribution. 



This is an extremely abundant insect throughout the East and 

 is frequently attracted to houses by light. It is found in all its 

 stages in manure heaps and accumulated vegetable debris. The 

 larvae are also reported to injure the roots of cane-cuttings in 

 sugar plantations, and the adult beetles are fond of the exudation 

 from damaged canes and are said even to make their way into 

 them. 



Although not provided with the beautiful stridulating structure 

 found upon the upper surface of the abdomen in related genera 

 which will be presently described, this insect is able to produce a 

 loud hissing sound by some means which has not been investigated. 

 It is perhaps caused by the compression and expulsion of air held 

 between the abdomen and elytra, but careful observation should 

 .soon reveal the source of the sound. That it is used as a means 

 of defence is shown by the following description from Lieut. -Col. 

 Cunningham's " Plagues and Pleasures of Life in Bengal." The 



* The length is always measured from the pygidium to the front of the 

 clypeus excluding any armature. 



