5Q [Mareh, 



The upper drawing, fig. 1, shows a side view of the median and one 

 lateral ridge, as seen by me under a 2" objective." 



If this material be removed the fir needle has much the appearance 

 of any other and one does not at first notice that anything has been done 

 to it. In certain lights, however, it can be seen that that margin of the 

 leaf is not quite of the same colour and texture as the rest. A closer 

 examination shows that an incision has been made just within the 

 margin of the (upper or inner or) concave surface of the leaf, but so 

 exactly has this been closed that it needs some care to determine that 

 there really is such an incision and its precise position. Below it is a 

 continuous cavity containing a series of eggs, one to each of the elements 

 of the outer incrustation. 



I have added to Plate III photographs of petioles of poplar with 

 eggs of GlacUus viminalis, that ought properly to have appeared on 

 page 11 of the last volume of this Magazine in connection with that 

 species, and a very fine photograph, also by Mr. Main, of the tip of a 

 willow leaf with eggs of P. {Nematus) salicis, a species that very closely 

 resembles C. viminalis, but is larger and, of coui'se, differs from it in 

 essential characters generically. 



In October 1917, I found eggs of P. sertifer laid in pine needles 

 exactly as described by Mr. Green. The chief point of interest I noted 

 was that until examined by transmitted light the needles seemed intact 

 and undisturbed. In November 1918, I obtained further needles in 

 which P. sertifer had laid in my jars. One afternoon I found a P. serti- 

 fer 2 with a little mass of green material just in front of the (retracted) 

 terebra. I fancied she had just been ovipositing, but the material may 

 have been there a considerable time, as I suppose that it ordinarily drops 

 away as soon as the egg is laid. This observation, however, is the only 

 one that disagrees with my suspicion that the eggs are laid in the dark. 



The eggs' then of P. 'pini and of P. sertifer are laid in the same 

 position in the pine needles, and the incision through which they are laid 

 closes up so as to be difficult to detect. The details, however, are very 

 different. P. pini lays her eggs in a continuous groove, P. sertifer in 

 separate pockets, which are from 2 to 3 mm. apart. The eggs are about 

 1-7 mm. long and 0-6 mm. in diameter, prolate spheroids. When F.pini 

 lays her eggs she removes the material from the continuous groove and 

 disposes it (with some other material provided by herself) along the 

 margin of the leaf over the groove. P. sertifer, on the other hand, 

 collects the material excavated in the form of a small mass of rounded 

 nodules, very like the frass of a larva, which gradually accumulates basal 



