198 Mr. P. Cameron 07i the 



G. septentrionalis (vide supra), is mucli less active, has 

 no coloured marks on the belly; it has the ventral glands, 

 but they are rarely protruded, nor has it (so far as I can 

 judge) a very bad odour; indeed, I could not feel any 

 from some specimens which I examined last year. Above 

 all, the larva of varus is of the same green as the alder 

 leaf upon which it feeds, and has no markings beyond 

 some slight black lines along the sides. It is thus less 

 noticeable than the other larvre, is more solitary in its 

 habits, and hence we can understand how it is not so 

 active, nor has such a bad smell as the others. 



I have stated before that many pine-feeding larvas are 

 coloured to resemble the pine leaves — either entirely 

 green, or green with a white lateral stripe. But this is 

 not the case with all of them. Lophyrus pini has a pale- 

 coloured larva with round black marks on the sides. It 

 feeds, too, in companies, frequently two or three dozen, if 

 not more, being found on the same shoot ; so that in this 

 way they form, Avhen massed together, very conspicuous 

 objects, the more especially as they strip the branches 

 almost completely of their leaves. The distinction of the 

 pini and virens larvffi is readily explainable by the fact 

 that the former exudes abundantly a resinous secretion, 

 which sticks firmly to the hand, while the latter does not 

 give out any. 



Many of the brightly-coloured saw-fly larvse have hairs 

 on the body, each issuing from a raised tubercle. These 

 hairs, however, ai'e not very thickly distributed over the 

 body, generally about a dozen or so to a segment, so that 

 they do not in any way obscure or hide the coloration. 

 The larva of Nematus ribesii is a case in point, and it 

 is not eaten by birds. A more conspicuous example 

 is found in the larva of Cladius viminalis, which is 

 orange with black markings, and they feed in a row, 

 three or four lying abreast and almost toviching each 

 other. All the larvae, however, of this class are not 

 brightly coloured. Thus, most of the larvse of Cladius 

 are pale coloured, or dark coloured on the back and white 

 at the sides. 



While there are no hairy larvjB among British saw- 

 flies comparable, — for instance, to caterpillars like the 

 tiger moth, — there are some Tenthredous larvje provided 

 with longish stiff-branched spines, which give their 

 bearers a very curious appearance. These spines are 

 black (as a rule) on the back, with green ones along the 



