1883.] 273 



legs black, ringed with ochreous at the joints ; some individuals still 

 bore the large roundish black spot above the foot of each veuti-al leg, 

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



The fifth moult occurred on 15th — 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, regained its glossiness ; the larva 



now did not so often assume its posture of contemplative repose, but 



seemed more intent on its consumption 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 fat and lethargic, until almost full 



fed, but when this stage was reached, it again was frequently to be 



seen in its more characteristic position ; when quite full grown the 



larva was of the length of 2 inches, and of thickness in proportion, 



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



defined ; the body cylindrical with plump segments deeply divided as 



far as the twelfth, and there tumid and humped with a slight dorsal 



ridge, thence sloping and tapei-ing a little on the very long front part 



of the thirteenth and still more on the short anal flap, deep wrinkles 



sub-dividing only the thoracic third and fourth segments ; the anterior 



legs rather small but set on large pectoral muscular fovmdations ; the 



ventral and anal legs stout w'ith well developed feet and hooks to secure. 



prehension and progression : the colour of the head is now pale 



bluish-green, the upper lip whitish or else pale yellow, the mouth black ; 



the back of a delicate pale yellowish-green becomes paler and opaque 



from the thoracic segments to the twelfth, blending gradually into a 



deeper brilliant yellowish transparent green on the sides and belly ; 



the slightly raised spots are all of pale primrose-yellow, the dorsal 



series are elongate-oval in shape, two on each segment one beyond the 



other in a broken line on the fifth to the eleventh inclusive ; the other 



series of spots are of round shape, such are the trapezoidally arranged 



fours of the back, the sub-dorsal broken line of threes, the lateral 



single spot, and the spiracular line of fours and the single spot below 



each spiracle, which itself is white, tenderly outlined with black ; a 



transverse series of four spots show faintly on the fourth segment, a 



small tumid side streak of the same yellow is on the third, and another 



conspicuously larger and longer is on the fourth slanting down obliquely 



forward ; on the back of the twelfth are two spots, and behind them 



on the summit two much larger spots united to a tumid curved streak 



of yellow ; a conspicuous tumid side streak of similar yellow begins 



behind the spiracle and tapers off on the margin of the anal flap ; the 



anterior legs are bright red, and outside each ventral leg is a roundish 



ring of black, the feet being furnished with brown hooks. 



