Walter Ritchie 320 



trees, but their colour accords exceedingly well with the ash-grey bark of 

 the twigs and branches (Plate XX, Left). During oviposit ion the female 

 is not a conspicuous object, as the basal portions of the stems chosen for 

 egg-laying are in many cases either covered with moss, the colour of 

 which blends well with the colour of the female, or she is entirely ob- 

 scured to view by ground vegetation surrounding the stems. So effective 

 is concealing colouration in this species, that until the eye gets accustomed 

 by search, it is very easy to pass the beetles over; on one occasion an 

 insect which was passed unnoticed, revealed itself by the stridulation 

 which followed a jarring of the twig, on the leaves of which the insect 

 was resting. 



The Larval Galleries. 



Of the numerous completed larval galleries examined by me on stems 

 not badly infested and where the larvae had room to work, one form of 

 gallery was met with far more frequently than any of the others. This 

 form may be taken as the typical gallery (see Fig. 23). 



For the sake of description the typical form of gallery may be divided 

 into four different portions, viz. (a) the initial or horizontal portion, 

 (b) the vertical portion, (c) the exit portion, and (d) the pupal portion. 



(a) The initial or horizontal portion. 



Upon issuing from the egg, the larva feeds at first upon the egg shell 

 and then proceeds to destroy the tissue immediately surrounding it, 

 viz. the inner bast layers and the cambium. In this way a minute shallow 

 roundish patch is formed. Later the larva works its way out of the egg 

 cavity or patch and cuts into the sapwood in a horizontal direction. 

 As it bores, some of the gnawed material is passed through its alimentary 

 canal, but far more is passed backwards into the gallery. As a rule the 

 sides of this horizontal portion of the gallery are very irregular in outline 

 and are deeply indented. The shape too of this portion is constantly 

 being altered, as the young larva returns along it, repeatedly widening 

 and deepening it, at the same time clearing away the frass or gnawed 

 material, so as to keep a free air-passage to the exterior through the 

 now gaping egg-bite. 



There is great variation in the length of this portion of the larval 

 gallery. In some cases it was fully one inch in length, while in others it 

 was only about half that length. 



(b) The vertical portion. 



When the initial portion is completed the larva turns downwards, 

 that is to say, at right angles to the first portion. As the larva tunnels 



