22 THE ENTOMOLOGIST. 



In order to complete the description of the full-grown 

 larvae, I must here add the following. The large white 

 tracheae could be seen through the skin, while the little 

 stigmata had pale brown borders. The last four thoracic legs 

 were glassy green, brownish at the tips, with a black longi- 

 tudinal mark on the upper side of the coxae. Although on 

 approaching or breathing on the larvae they turned the 

 abdomen smartly about, I could not perceive any glands on 

 the ventral surface, such as are found in the genus Nematus. 

 Lastly, the anal valve was of a more decided yellow than the 

 middle of the back, the margin having eight minute brown 

 teeth, of which those on the sides were very indistinct. 



On the whole, the larvae much resembled those of Nematus 

 septentrionalis, L., described by me in the second volume of 

 these Transactions ('Zoologist,' 1st series, p. 8175), and of 

 which a figure is given on pi. V., figs. 1 and 2; but these 

 latter have, very distinctly, ventral glands. 



This seems a fit opportunity to add, with reference to the 

 above-named species of Nematus, that later observations 

 have taught me that it lives not only on the alder, but also on 

 birch ; that is to say, unless the insect found on birch is 

 merely a very nearly -allied species, which only differs from 

 Septentrionalis in the colour of the intermediate legs of the 

 imago. For example: — In June, 1862, I found larvae on 

 birch, which appeared to me not to differ on any point from 

 those found on alder. They spun up on the 17th of June ; 

 and during the interval between the 19th of July and the 

 21st of August a nun)ber of females were produced agreeing 

 with the above description of Septentrionalis, with this single 

 exception, namely, the tibiae of the intermediate pair were 

 not pale red annulaled with white at the base, but were white 

 for half their length from the base, the remainder being 

 black, and the tarsi of the same pair were black instead of 

 pale red. 



I'he larvae of Dineura rufa spun cocoons made of grains of 

 earth, resembling those of so many other species. The pupae 

 I have not yet seen. As in the case of many other sawflies, 

 the imauo is much less common than the larva. 



Zygoma Vanadis or Zyyeetia exuUnis var. Vanadi.s, a 

 British Insect. — My readers will recollect that the following 



