Highland Insects. 133 



phants of the true wood-feeders, among which they have 

 hitherto been considered to rank (as far as selection of food 

 goes), until M. Perris, a distinguished French entomolo- 

 gist, pointed out their true relations with regard to the Xylo- 

 pliaga. From his observations (which I have been enabled to 

 corroborate in a great measure) it appears that the species of 

 Ips and Rhizophagus enter the holes made in the fir-trees 

 (either in chinks of the bark, where there is the thinnest space 

 between the inner and outer coatings, or, in the case of felled 

 stumps, at the junction of the bark and wood) by the Hylastes, 

 and lay their eggs in the galleries made by the latter, on whose 

 larvae their larvse feed. M. Perris has observed the larvae of 

 the common R. depressus with half their bodies plunged into 

 the larvae or pupae of Hylesinus or Hylastes, devouring them ; 

 and I have myself seen the same species half immersed in a 

 sickly specimen of a perfect Hylurgus pimperda.* 



At the junction of the bark and solid wood in freshly-cut 

 stumps, the female of Pissodes pini, a large and very prettily 

 marked northern species of weevil, may be constantly seen, 

 laboriously drilling round holes with its rostrum, in which to 

 deposit eggs. Its fat, full-grown larva, or the pupa in a 

 gnawed out cell, may often be found near the ground, to which 

 it has eaten its way under the bark ; where also its ally, the 

 still larger Hylobius dbietis — a clumsy, dull black, delicately 

 yellow marked Curculio, of very clinging habits as to its tarsi — 

 undergoes its changes, and may be found copiously. The 

 latter insect has been imported in Scotch timber (in the larval 

 state) to the south, where it is not uncommon. 



These species, though constantly wood-feeders, exhibit 

 a great difference in structure to certain other tree-fre- 

 quenters ; their heavy bulk being strongly contrasted by the 

 thin, flat, elegant, long-limbed, Dendrophagus crenatus, a very 

 rare sub-cortical species, which I found coursing rapidly, 

 towards evening, over a bare stump ; and by the cylindrical 

 Xyloterus lineatus, which undergoes its changes deep in the 

 solid wood, drilling a small, neat shot-hole through to the 

 surface at right-angles from the centre, and lurking at the 

 mouth of its burrow, into which it retreats backwards on the 

 least alarm. A similar, but larger, hole is drilled in the very 

 hardest pines by the larva of Hyleccetus dermestoides, which 

 nothing but a woodman's axe can circumvent. The exceed- 

 ingly flimsy material of which this curious elongate Malaco- 



* Certain species of JSpurcea — small flat testaceous beetles, often seen in 

 flowers and fungi, or at the exuding sap of trees — are also attendants upon the 

 larvse of the small wood-feeders ; one especially, JE. pusilla (conspicuous through 

 the arched middle tibise of its male), thronging the galleries. I imagine that they 

 are attracted by the wet frass and sappy exudations caused by the operations of 

 the Xylophaga. 



