ELM-BARK BEETLE. 217 



The burrow of the parent beetle is usually about three to 

 five inches long, and takes about three weeks to form. The 

 eggs are laid along each side of it, and are a hundred and 

 upwards in number. As many as a hundred and sixty have 

 been observed. 



The young grubs, when hatched, start at right angles from 

 the parent gallery, and gnaw their way onwards, the burrows 

 gradually increasing in size and curving to allow room for the 

 growing size of the tenant (as shown in the fig., p. 216). 



Most of the larvse are full fed towards the end of July, when 

 some turn to pupae at the end of their burrows, and the 

 beetles from these pierce the bark and come out from the tree 

 during August. The greater number, however, of the grubs, 

 appear to form a httle chamber, either just within the wood 

 or in the thick bark, where they pass the winter, and come 

 out as beetles about the end of May ; thus, in case of the 

 bark being removed or falling from the tree, although the 

 beetle-maggots in the open galleries beneath it are exposed, to 

 be cleared ofl' by the birds, the others buried in their 

 chambers, with the openings stopped up by the rejected 

 matter, are safe from attack. 



The maggot is whitish, curved, tapering bluntly to the tail, 

 fleshy, much wrinkled across and legless. 



The beetles are black, from an eighth to a quarter of an 

 inch in length, with rounded rough head and reddish horns ; 

 wing-cases rounded at the sides, and cut short at the tip, 

 pitted lengthwise with rows of dots, with irregular punctures 

 between, glossy, and sometimes of a pitchy colour or rusty 

 red ; abdomen cut short, slantwise beneath ; legs pitchy ; feet 

 reddish. 



It has been observed that these beetles prefer a tree that 

 has already been attacked rather than a young and vigorous 

 one, and it is easy to tell where they are or have been present 

 by the great number of small holes, as if the bark had been 

 pierced by shot or holes made by a brad-awl, and also (whilst 

 the beetles are boring their way out) by the wood-dust 

 observable on the bark, or fallen on the ground beneath the 

 openings of their burrows. 



The circumstance of Scolytus attack, and sickly growth of 

 the tree or decay of the bark occurring together, has given 

 rise to much discussion as to whether the Scolijtns attack 

 caused the decay, or weakened health induced attack. 



It is observed by Dr. Chapman, from whom I take much 

 of the above life-history (see ' Entomologist's Monthly Maga- 

 zine,' 1861), pp. 12G, 'l27), that healthy growing trees are 

 supposed to repel the attacks of this genus of beetles by 

 pouring sap into their burrows. He notes that in the case of 



