1919.] 



The largest number of eggs apparently laid at one time was eleven ; 

 these ai"e laid in a series on one side of the twig, beginning close to the 

 end and extending downwards for about 27"0 mm. The twig is about 

 100 mm, long and 3 mm. wide at the base and 2'5 mm. at the thinnest 

 j)ortion. The position of each egg is marked by a rounded and almost 

 circular elevation of the surface of the bark, actually from l'8-2"0 mm. 

 across and 2'0-2'3 mm. in the line of the twig ; each is made separately, 

 and may touch its next neighbour or be separated by an interval of as 

 much as 0"8 mm. The incision of entry is quite visible as a darker line 



Rough diagrams to show disposition of egg, enlarged about 6 times. 



A. Portion of twig with two eggs. 



B. An egg in position with film of bark raised. 



C. Longitudinal section through egg, 



D. Transverse section through egg, 



1. Mark of incision. 2. Film of surface-bark (dead ?), 3. Film of surface-bark over 

 egg raised. 4. Layer of green living bark. 5. Egg. 6. Adventitious gi-owth 

 surrounding egg- 



down one side, and appears to have the margins slightly separated ; it is 

 J.-0 mm. long, varying very little. One would expect the wound to 

 remain a little open, since the presence of the egg raises the bark so that 

 it cannot easily close up, and the bark is no longer actively alive and 

 capable of healing over, in the way that usually occurs when a sawfly 

 lays in growing leaves and stems, sometimes quite oblitei-ating the line 

 of entry. There appears, however, to be some consolidated exudation in 

 the wound, closing it up, derived no doubt from the deeper, more living, 

 tissues in which the egg is placed. 



The incision of entry is sometimes on one side, sometimes on the 

 other of the egg-pocket, as one looks at them with the twig held upright. 



