161 



NOTE ON THE LIFE HISTORY OF ABDERA 

 BIFASCIATA, Marsh. 



By T. ALGERNON CHAPJIAN, M.D., Abergavenny. 



My attention was one day attracted by a rotten oak stick lying on the 

 ground, from the circumstance that the bark on one side presented numerous 

 minute circular holes, irregularly disposed. My immediate conclusion was that 

 I had come across traces of some Tomicus ; but on cutting into the stick I found 

 that each hole led into a little cul-de-sac, from a quarter to a third of an inch 

 long, lying parallel with the fibres of the wood. This was obviously the work 

 of some insect, but clearly not of any Hylesinidon. I was further puzzled by 

 the inadequateness of the removed material to have fed an insect of the size 

 indicated by the exit aperture. 



I have not since met with any stick containing these holes so abundantly 

 as this first one did; but I soon after found sticks similarly perforated, and 

 almost invariably found the holes associated with the presence on the stick of 

 the remaiLS of a fungus ; and last spring I succeeded in finding sticks still 

 inhabited by the larvae of the insect that produces these holes. The reason 

 that my first specimen was so puzzling was that all traces of the fungus had 

 disappeared. 



The beetle (for the larvae in question are those of a beetle) whose history 

 I was thus led to investigate proved to be Ahdera btfasciata, Marsh., an insect of 

 some rarity. 



I have said that I usually found the indications of the presence of the 

 beetle associated with a fungus. The larvae in reality feed not on the oak 

 wood, but on the fungus, and I never find the fungus in any quantity without 

 indications of the beetle. Though an enthusiastic mycophagist, I caimot lay 

 claim to any knowledge of mycology, and am consequently indebted to Dr. Bull 

 for the knowledge that the fungus inhabited by Ahdira bifasciata is the 

 Corticium qiiercinum. Ft., and it is only to be found in its proper habitat. Its 

 only habitat, so far as my observations go, is on those branches of trees from one 

 to three inches in diameter, which die and become rotten on the tree. It grows 

 on the under sides of these branches, and though only I suppose really alive for 

 one season, its dry remains may persist for several years, and when soaked with 

 rain look much like the fresh fungus. Its favourite tree is the oak ; I have also 

 found it on the ash. Such rotten branches as the Corticium affects are usually 

 broken ofi^ piecemeal by the wind, and should they happen to fall when the 



