The Zoologist— December, 1869. 1947 



Life-Histories of Sawflies. Translated from the Dutch of M. S. C. 

 Snellen van Vollenhoven, by J- W. May, Esq. 



(Continued from S. S. 1736.) 



Nematus Betol^, Hartig. 

 De Geer, Memoires (Goetze's translation), ii. 2, p. 261, tab. 87, fig. 23. 

 Harlig, Blatt und Holzwespen, p. 219. 



Nematus fulvus, capite fusco, thoracis dorso ac pectore nigro 

 maculato, alis iridescentibus, stigmata fusco luteo-raarginato, 

 tarsis poslicis fuscescenlibus. 



We are, I believe, indebted to De Geer for all that is at present 

 known about this insect. Hartig has simply copied the description 

 of the Swedish naturalist, and appears never to have seen the insect 

 alive, either as larva or imago. De Geer's very short description 

 comes after that of Nematus perspicillarus. King, which species is 

 mentioned by Hartig under the name of Nematus melanocephalus, 

 and agrees very closely with the one undei consideration. 



I had at first intended to have followed the example of my prede- 

 cessors, and treated of these insects in succession : I was, however, 

 afraid that this would oblige me to postpone both descriptions for too 

 long a time, as I have not met with the larvae of perspicillaris 

 during the last fourteen years, and my drawings only give the larva in 

 its very early and its latest stages ; I also found that I had no repre- 

 sentation either of the pupa, the cocoon, the egg or the perfect insect : 

 I thus thought it better to divide them, however nearly they may be 

 related, and describe, in the first instance, the metamorphosis of 

 Betulse, the less known of the two species. 



Having by means of her saw made openings in a birch leaf, the 

 female deposits her eggs between the epidermis and the parenchyma, 

 on the under side of the leaf. I found some leaves, which had been 

 thus attacked, on a small birch tree in my garden, early in June, 1862. 

 The larvae on quitting the egg were entirely of a blackish green colour, 

 and ate out the substance of the leaf between the veins, but left un- 

 touched the point of the leaf, as also the places or little receptacles in 

 which the empty egg-shells were concealed, so that in this condition 

 the leaf had the appearance of our fig. 6, in which a a represents the 

 places where the eggs have been deposited. 



After the first moult the young larvae were of the size" repre- 

 sented at fig. 2 on our plate j fig. 3 representing the same larva 



