166 THE CANADIAN ENTOMOLOGIST. 



Second Instar. — The shape is as in latter part of first instar. 

 Head, at first pale green, as the caterpilllar gets older changing to 

 brown ; shining. 



Colour blue-green. The minute black dots which studded the surface 

 in the first instar have now entirely disappeared. 



The bristle-bearing tubercles are much more numerous than in the 

 first instar. The inner dorsal row of long, backwardly-curved bristles is 

 conspicuous, the substigmatal fringe less so, because its bristles are some- 

 what shorter. Between these two series of bristles the surface is richly 

 clothed with tubercles which bear short bristles, but the precise arrange- 

 ment of these tubercles in rows, as in the first instar, is not evident. 



Between the substigmatal fold, which appears as a white line, and the 

 mid-dorsum are four faint lines interrupted at the sutures. 



The thoracic shield is represented by a pit. 



Mandibles brown, ocelli black, these remaining the same in succeed- 

 ing instars. 



Length, 2 mm. to 2.K mm. 



Third Instar. — Shape similar ; the caterpillar now appears longer, 

 however, in proportion to its width. 



Head pale green. 



Colour blue-green (in one example pale green), later in the instar 

 becoming pale green. 



The substigmatal fringe of bristles and dorsal row of backwardly- 

 directed bristles are still present, the latter less curved, relatively shorter 

 and less conspicuous; the region between these two series of bristles is 

 well clothed with bristle-bearing tubercles, the bristles short ; tubercles 

 without bristles few. In this instar a new element in the clothing usually 

 appears for the first time ; this is an opaque, white, egg-shaped process 

 borne by a short pedicel, the latter arising from a tubercle. These 

 processes are fewjn number, irregularly placed and often found cephalad. 

 In the examination of several caterpillars they varied in number from six 

 to twenty-five, while in one example none at all could be discovered. 



There are four faint, uneven white lines as before, the two upper ones 

 being wider, and all becoming more distinct as the caterpillar approaches 

 the end of the instar. 



Length, 3 mm. to 4.5 mm. Average of 22 caterpillars, 3.7 mm. 



Fourth Instar. — Shape as before ; the arching of the segments be- 

 tween the sutures has gradually been reduced as the caterpillar has grown 

 older. 



