CH. XVII.] VARIOUS SPECIES OP SAWFLIES. 253 



much avidity upon other soft-bodied insects, even 

 attacking the beetles commonly termed soldiers and 

 sailors (Telephorida), which are themselves equally 

 ravenous towards other insects. It certainly appears 

 a remarkable circumstance that some species, which 

 in their larva state are eminently herbivorous, should 

 become, in their perfect state, real cannibals ; unless, 

 indeed, it be supposed that they were actually star- 

 ving for want of their appropriate food ; but these 

 species even devour their prey in the midst of flow- 

 ers, especially those of the umbelliferous kinds, the 

 honey of which they will leave for that purpose, as 

 we have repeatedly witnessed ; indeed, it would 

 seem that they select these kinds of plants in order 

 to seize upon the numerous flies, &c. which fre- 

 quent them. 



The antennae of these insects are strongly vibra- 

 tile, and appear to perform the office of feeling the 

 surrounding objects. The small species instantly 

 fold.these organs, as well as the legs, upon the breast, 

 and fall to the ground immoveable on the least ap- 

 proach of danger. 



The history of one of the species of this family 

 is recorded by Mr. Marshall, in the Philosophical 

 Transactions for 1783 : it attacks the turnip after it 

 has escaped the ravages of the turnipfly, or Black 

 Jack (Haltica nemorum), and often occasions so much 

 damage that whole, districts are sometimes nearly 

 stripped ; indeed, in that year many thousands of 

 acres were obliged to be ploughed up in consequence 

 of their attacks. The sudden appearance of such 

 vast numbers of these insects appears to have given 

 rise to various conjectures; Mr. Marshall, indeed, 

 states, that it was the general opinion in Norfolk that 

 they came over the sea ; and a farmer actually de- 

 clared that he saw them arrive in clouds so as to 

 darken the air ; and the fishermen asserted that they 

 had repeatedly seen swarms of them pass over their 

 heads when they were at a distance from the land. 



VOL. II. Y 



