Gryplialus.~\ RHTXCHOPHORA. 429 



two of these trees, which aro from twenty to thirty years old, had been 

 blown over in a manner similar to that in which poplars often suffer, 

 viz., they had been snapped across at about the level of their lower 

 branches ; one of them had fallen last winter, the other during the 

 previous one. On both I found evidence of their having begun to 

 decay before they yielded to the storm, but the more recent one was 

 still so far alive as to be attempting to throw out leaves, yet many of 

 its branches had long been dead and one side of the stem was so also ; 

 this I soon found to be caused by a small beetle belonging to the family 

 Hylesinid>:e. This beetle, Cryphdlus binoJnlu*, Eatz., appears not to 

 have been taken in England since its original capture by Mr. E. AV. 

 Janson at Highgate ; and I may observe that very few of my specimens 

 present the (sexual) spines at the apex of the elytra ; and that, when 

 present, the spines are very small. This species, unlike Hylesinus 

 creiiatus, which commences its attack close to the ground, first attacks 

 the branches and then advances downwards. A colony is probably 

 commenced by one, or only a few pairs ; but they rapidly multiply. 

 There are about a dozen of the young aspen trees (Populiu tremula) on 

 which I find them, and of these, besides the two already mentioned, 

 they have this season killed a third tree. The leaves which it threw 

 out abundantly last spring are now all black and dead, and I suspect 

 that this is entirely the work of the present season. A fourth tree is 

 far gone and several others are invaded. Like most of the Xylophaga 

 it only attacks the bark. In the genus Hylesinus, and others of the 

 family, the parent beetles make a long straight burrow, and the eggs 

 are deposited more or less regularly along either side. Unlike these, 

 Cryplidlus Hnodulus makes what may be called a little irregular cavern 

 rather than a burrow. This is always immediately beneath the outer 

 bark, and does not penetrate to the wood. I find invariably a pair of 

 beetles in each cavern, even when nearly all the eggs are deposited, or 

 when the eggs are hatched ; these are laid in little confused heaps in 

 the recesses of the cavern, sometimes all in one heap, generally in three 

 or four, and to the number of from thirty to sixty. The larvae when 

 hatched burrow without any regularity, but tend to travel in a vertical 

 direction. They are footless grubs, with strong jaws, and a distinct 

 head like the larvae of the other XylopJiaga. I found that the eggs 

 laid in May had in August produced some perfect beetles, though many 

 still remained in the larval and pupal states. This has also been the case 

 this season with HyJemtida I have been watching, and I suspect that 

 this species, like the others, does not usually come to maturity until a 

 month or two later, and then hybernates before emerging. This species 

 appears only to attack the living trees, and though so minute, is from 

 its numbers able to cause the destruction of any tree it colonises. A 

 branch is usually first attacked by several pairs, whose progeny then, 

 laying their eggs in it, complete its destruction. AVherever a brood 

 has been reared a wide rough crack is observable in the bark, and a 



