ON THE CATERPILLARS OF THE SAW-FLIES. 123 



And 3. A Tabular Sketch of the chief variations exhibited 

 in the structure of Tenthredinideous larva?. 



I. It had been suggested to me, that an acconnt of the 



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transformations of the saw-flies, with especial reference to 

 their resemblance to Lepidoptera, would be useful to many 

 young Entomologists, who, for want of some such sketch, 

 and ignorant of the characters of the Tenth redinidce in their 

 earlier states, may have wasted their time and attention on 

 caterpillars which they had hoped would have produced 

 some rare moth, but which only yielded " a nasty saw-fly," 

 or, who having reared a saw-fly from what they had sup- 

 posed was the larva of a Lepidopterous insect, may have 

 come to the false conclusion, that the saw-fly was a parasitic 

 insect, and may, perhaps, have mistaken it for an Ichneumon 



It may be advisable to observe shortly, that the females 

 of all the species of the family Tenthrediniclce are provided 

 with an instrument at the extremity of the body beneath, 

 resembling a pair of saws, with which they form grooves 

 in leaves or twigs, for the deposition of their eggs. The 

 caterpillars, hatched from these eggs, bear so great a resem- 

 blance to the true caterpillars of Lepidoptera, that several 

 otherwise deservedly esteemed writers have mistaken them 

 for the latter. Such was the case with Goedart (Obs. No. 

 77, letters A. and B.), and his commentator Lister, who, 

 supposing that such larvae only produced Lepidopterous 

 insects, fancied that the two saw-flies reared by Goedart 

 were parasites. 



The external tegument of the body, as well as the general 

 form of the larvae of saw-flies, is very similar to that of the 

 true caterpillars ; the bodies of both are variously coloured, 



