* Insects, 



7855 



Life- Histories of Sawjiies, Translated from the Dutch of M. Snellen 

 Van Vollenhoven. By J. \V. May, Esq. 



(Continued from p. 7724.) 



Nematus vallator, V. Voll. 

 Larva and imago both uncle scribed. 



Nematus niger, nitidus, antennis crassioribus, pedibus rufo-flavis, 

 tibiis posterioribns dimidiato albis nigrisque. 



The insect which I am now about to describe belongs undoubtedly 

 to the genus Nematus, although possessing two peculiarities in the 

 direction of the genus Cladius ; thus the antenna), especially in the 

 male, are vertically incrassated, and the terminations of the joints 

 form somewhat hook-shaped projections, as shown at fig. 5; on the 

 other hand, the second recurrent nervure is not exactly received by 

 the second submarginal cell, but, in the male, by the nervure between 

 the second and third submarginal. Nematus vallator is, however, far 

 more remarkable by its habits and economy than on account of any 

 structural peculiarities, its habits being so singular that I have found 

 nothing similar in the history of any other insect. 



In the garden at the back of my house stands an Italian poplar 

 which has been planted about ten years, and on one occasion, in the 

 month of May, looking among the foliage in search of any insects 

 which might be little known or entirely unknown to me, I was sur- 

 prised to perceive some little white projecting points round the holes 

 which had been eaten in the centre of some of the leaves; these pro- 

 jections appeared erected on the surface of the leaf. I could not at 

 that moment detect any animal to which I could attribute this struc- 

 ture ; but my curiosity was aroused, and I resolved to watch the tree 

 in question. It was not long before I discovered the origin of the 

 white plantation. I found in some of the holes in the leaves a num- 

 ber of little saw-fly larvae with the palisades surrounding the holes ; 

 I placed these larvae in a glass. The following day I found new 

 erections on fresh leaves which I had put into the glass, and on 

 taking another look at my poplar, in the evening, I saw two larvae at 

 work making this singular fortification. 



When the palisade larva, if I may so call it, has selected a leaf 

 which it intends to feed upon, it turns round so soon as it has got on 

 to the leaf-stalk, and then, with its body on the leaf, and its head and 

 two or three anterior segments on the leaf-stalk, it makes a sort of 



