196 



Memoirs of the Indian Museum. 



[Vol. Ill, 



Nilgiris, is almost certainly a synonym of Basilianus neelgherriensis ' ; and, as the genus 

 Basilianus is most unlikely to occur in the St. Cruz islands, the probability is either 

 that there has been some mistake about the locality from which the only other 

 species — E. infantilis — comes', or else that this species has true scars on the mentum 

 which have not 3^et been described. Consequently the genus Epilachcs is not included 

 in the following key. The genus Heterochilus, for which Zang (19056, p. 154) has 

 suggested the new name Rhipsaipis , does not appear to me to be sufficiently distinct 

 for recognition, especially in view of Zang's notes upon it (1905^, p. 167). The genus 

 Ophrvgonius, Zang, is very close to Basilianus, Kaup; but as the characters by which 

 the two are separated do undoubtedly distinguish all the Indian forms on the one 

 hand from the only Malaysian form with which they could be confounded on the other, 

 I have found it convenient to retain it." 



The genera which I recognize in the subfamily Aceraiinae may be distinguished 

 from one another, thus^: — 



; i-A as long as that separating 



space 



times as long as that 



( Inner tubercles separated by a sf: 

 outer tubercles 



Inner tubefcles separated by a 



' separating outer tubercles 

 Anterior margin of head symmetrical or but slightly asymmetrical, 

 both right and left outer tubercles simply pointed 



^ Anterior margin of head markedly asymmetrical, left external 



i tubercle longer than right, rounded or more or less obliquely truncate 



V^at apex 

 Central area of mentum smooth, neither grooved nor depressed near 

 middle of anterior margin ; anterior margin of head quite symme- 

 trical 



Central area of mentum grooved or depressed round a median (rarely 

 paired) process close to anterior margin; anterior margin of head 

 more or less asymmetrical 



Frontal ridges represented by line grooves (which in certain speci- 

 mens are somewhat obscured by their posterior margins being deve- 

 loped into ridges} ; antennae with five or six pubescent lamellae ; 

 lateral grooves of elytra narrow, their punctures never linear 

 Frontal ridges neither represented nor accompanied by grooves ; 

 antennae with only four pubescent lamellae ; lateral grooves of elytra 

 broad, their punctures transversely linear .. 



Tibcrioidcs, Gravely 

 2X5 & 280. 



217 & 



Kaiip 



Chiloiiuiziis, Zang ;.pp 



& 28 1. 



O/yltryi^oniiis, 

 227 & 285 



218 



Zang ; pp 



' I have since been able to con6rm these two suggestions by reference to the type of /:. iiifanlilis 

 and cotypes of /; fdiiis; see below, p. 283. 



'^ For a modification of the views e.'<pressed here see Appendix I, pp. 316-318. The page- references 

 given in this key refer to the pages of the present paper on which are described the first species of each 

 of the genera as here defined. The shifting of the points of division between the genera has not 

 necessitated any change in the oider in which the species would have been described. 



