THE GHOST MOTH AND THE GOAT MOTH. 307 



males fly quickly to and fro over the same spot for a 

 considerable time. The favourite food of the larva 

 consists of the roots of burdocks, which, as is well 

 known, are very abundant in churchyards, and as 

 it is in such situations that the male Ghost Moth is 

 usually seen, sweeping swiftly about just as the twi- 

 light begins to deepen into darkness, it is, perhaps, 

 not much to be wondered at if his pure white wings, 

 thus seen, have suggested a comparison with the sheet, 

 which has from time immemorial been the traditional 

 vesture of most apparitions. 



A few species, allied to the Ghost Moth, agree with 

 it in their mode of life, except that they do not con- 

 fine themselves so strictly to a single spot; whilst 

 others, instead of devouring the roots of plants, feed 

 upon the wood of various trees, boring large galleries 

 into their substance and thus frequently destroying 

 them. Of these, only two species occur in Britain, 

 one of which must rank amongst our largest Lepi- 

 dopterous insects, as the wings of the female some- 

 times measure four inches across, although the male is 

 considerably smaller. This insect is the Goat Moth 

 (Cossus ligniperda], the dark red fleshy caterpillar of 

 which feeds in the interior of the trunks of willows, 

 and also occasionally of other trees, sometimes re- 

 ducing these to such a state by its burrows, that a 

 moderately strong wind is sufficient to blow the trees 

 down. The damage which this larva must do to the 

 trees in which it takes up its residence in any num- 

 bers, is evident from its great size, the full-grown 

 caterpillar measuring four inches in length, with a 

 proportionate thickness, and from the fact of its 

 passing more than two years before changing into the 

 pupa state, so that occasionally it is even compelled 



