PETASIA NUEECULOSA. / 



pieces out of the leaves at intervals, and at other times 

 were to be seen for long periods hanging to the birch 

 sprays motionless in their singular attitude of repose, 

 but yet so suggestive of great muscular exertion and 

 watchfulness. Their growth now seemed rapid, as in 

 the course of three days they were observed, when in 

 motion, to be an inch and three lines long, stout, and 

 thickest behind, their colouring of the same light green 

 as before, the upper surface bearing rather warty 

 spots of bright yellow and slash-like streaks of the 

 same yellow on the thoracic and posterior segments ; 

 the anterior legs black, ringed with ochreous at the 

 joints. Some individuals still bore the large roundish 

 black spot above the foot of each ventral proleg, while 

 others had only a black outline of it, or part of it. 



The fifth moult occurred between the 15th and 19th 

 of June, and for a time after this operation the head 

 was of rougher texture than heretofore, but gradually 

 in three or four days it regained its glossiness. The 

 larva did not now so often assume its posture of con- 

 templative repose, but seemed more intent on its con- 

 sumption of food, and in the shorter intervals of rest 

 was to be seen lying quite at full length, or in a gentle 

 curve, along the birch twigs, quite flat and lethargic, 

 until almost full-fed; but when this stage was reached, 

 it was again frequently to be seen in its more charac- 

 teristic position. When quite full-grown the larva was 

 2 inches in length and of thickness in proportion, 

 with a very soft skin ; the head full and rounded, with 

 lobes slightly defined ; the body cylindrical, with plump 

 segments deeply divided as far as the twelfth, and 

 there tumid and humped with a slight dorsal ridge, 

 then sloping, and tapering a little on the very long 

 front part of the thirteenth and still more on the short 

 anal flap, deep wrinkles subdividing only the thoracic 

 third and fourth segments. The anterior legs rather 

 small, but set on large pectoral muscular foundations ; 

 the ventral and anal prolegs stout, with well-developed 

 feet, and hooks to secure prehension and progression. 



