48 THE MEANS OF PRESERVING TIMBER FROM INSECTS 



The middle or body of this singular impression is the pas- 

 sage which has been formed between the bark and the wood, 

 or rather within the thickness, to a certain extent, of both, by 

 the female insect, depositing her eggs, on each side, in her 

 course, until she is exhausted of them, when she dies, and may 

 accordingly generally be found at the extremity of the chan- 

 nel ; the deposition of her eggs being to her, as to most other 

 winged insects, the immediate forerunner of death. From this 

 tubular path, however, the larvae which are hatched from these 

 eggs, deposited very close to each other, in the shape of little 

 white worms, or grubs, destitute of legs, proceed nearly at 

 right angles, eating their way in smaller tubes parallel to each 

 other, which, lying close together, serve effectually to separate 

 the bark from the tree. The larvae remain feeding in the tree, 

 generally in this situation, throughout the winter. During 

 that season, the sap of the tree being down, the bark adheres 

 less firmly, the grubs work with greater facility, and the mis- 

 chief is consequently augmented. About the commencement 

 of spring they assume the Pupa or Nymph state that con- 

 dition or stage of their metamorphosis, which in butterflies we 

 are accustomed to call the Chrysalis (from its golden colour 

 in many of those insects) ; and before the end of spring, the 

 bark of an infected tree begins to appear as if all its cre- 

 vices were full of a very fine sawdust. The last change of the 

 insect takes place; and being now winged, it endeavours to 

 arrive at the external air, for the purpose of propagating its 

 species, and laying its eggs in other trees. Each hole, which 

 now appears as if made with a gimlet, marks the exit of a perfect 

 insect. In the first instance the voracity of the larvae, and in 

 the second, the endeavours of the perfect insects to liberate 

 themselves from the wood, particularly when such attempts 

 are made by almost incalculable numbers, soon occasion the 

 bark to fall in large pieces. The consequence is that the new 

 leaves only make their appearance to wither, and the tree pe- 

 rishes. 



Now it is evident from these facts, that the tremendous 

 ravages of these insects these small beetles which thus ren- 

 der themselves more formidable to mankind than the strong- 

 est and most ferocious beasts of prey, might have been pre- 

 vented, and the evil repressed at its commencement, had the 

 possessors or inspectors of the trees been acquainted with the 

 Natural History of the insects ; and it is this knowledge alone 

 which could have enabled them effectually to have done so. 



We have found that in their perfect state as winged bee- 

 tles, the insects are the most formidable, having attained the 

 power of propagating the disease from one tree to many 

 others. But it is also from an accurate knowledge of them 



