70 ROOKS AND THEIK MORALS 



nettles, a diet which nobody will grudge them. The great 

 family of the Fritillaries feed upon various kinds of wild- 

 flowers, and the grub of the Painted Lady upon thistles, 

 varied occasionally with nettles. Of the hawk-moths, 

 only the Great Death's Head can be regarded with 

 jealousy by the farmer, feeding as it does upon leaves of 

 the potato ; and Death's Heads are of such rare occurrence 

 in this country that nobody can show two penn'orth of 

 damage from their agency as caterpillars. All the other 

 hawk-moths browse upon the leaves of trees or weeds. 

 In fact, the only caterpillars that do any appreciable 

 damage to farm or garden hi the United Kingdom are 

 those of the large and small white butterflies, and some 

 of the moths, such as the pretty Magpie or Currant Moth. 

 I am not aware that anything has been proved to the 

 discredit of the Tortoise beetle, that creature of brilliant 

 shining armour, whose larva has the strange habit of 

 covering itself with a greatcoat formed out of its own 

 excrement. Of the good of PhyUopertha, Anisoplia, and 

 Hoplia I cannot speak, having no information on the 

 subject; but the burying beetles (Necrophorws) and the 

 carrion beetles (Silpha) contain but one mischievous 

 member in their families (SilpJia opaca) which has 

 abandoned the universally carnivorous diet of its relatives 

 and attacks the sugar beet, which is not grown in Great 

 Britain. All the others must be accounted beneficial in 

 their operations, subsisting almost exclusively on decom- 

 posing animal or vegetable matter, though a few species 

 attack and devour other land insects. In respect of the 

 hair-gnats (Bibio), which Dr. Hollrung reckons injurious, 

 Mr. David Sharp's opinion may be quoted as that of a 

 good and recent authority 



