AEGUS CAPITATUS. 229 



NOTE XLVIII. 

 ON AEGUS CAPITATUS, WESTW. 



C. RITSEMA Oz. 



Among the Lucanidae brought together iu Deli (East- 

 Sumatra) by Dr. B. Hagen and presented by him to the 

 Leyden Museum, I found a male specimen of minor deve- 

 lopment , belonging to the genus Aegus , which was at first 

 sight unknown to me. A careful examination , however , 

 convinced me of its close relationship with Aegus capitatus 

 Westw., a species represented in Dr. Hagen's collection by 

 a few males and females, but I could not decide whether 

 it was the extreme varietas minor of this species or that 

 of a new one. I wrote therefore to Mr. Neervoort van de 

 Poll asking him to look at the matter , and most courteously 

 he sent me from his extensive collections all connecting 

 links between my specimen and the varietas major of Aegus 

 capitatus. 



Taking into consideration that among the described forms 

 of the male of this species the smallest form (that what 

 I regard as the true var. minor) is not to be found, I 

 thought it not without interest to publish a detailed des- 

 cription of it. With the higher developed forms it has some 

 important characteristics in common, viz.: the shape of the 

 inner edge of the mandibles with the conical basal tooth 

 on a level below that of the surface ; the shape of the fore 

 margin of the head between the mandibles (broadly and 

 angularly emarginate, the emargination terminating in a 

 produced point at each end); the shape of the hinder an- 



Notes from the Leyden Museum, Vol. XI. 



