THE CANADIAN ENTOMOLOGIST. 45 



bluish above. Sub-lateral, jet black, with pale blue apices. The dots 

 between the dorsal and lateral rows of tubercles are much smaller than 

 formerly, and have actually disappeared in several instances. Between 

 the lateral and sub-lateral rows they are nearly gone in front, and entirely so 

 behind. Upon the abdominal pro-legs they are broader below, and rapidly 

 diminishing above. On the anal pro-legs, the tw^o confluent spots have 

 separated and grown elliptical in shape. That upon the head is somewhat 

 longer and broader. 



The jaws, lips and palpi have become more conspicuously colored, 

 approaching the color of these parts in the mature caterpillar. 



The spiracles, which all along occupied a middle lateral position on 

 the ist, 3rd, 4th, 5th, 6th, 7th, 8th, 9th, lothand nth somites, but, without 

 being easily recognized from resemblance in color to surrounding parts, 

 are now quite conspicuous. They are narrowly elliptical in contour, with 

 the longest diameter arranged transversely, and have cream-colored 

 centres with black borders. 



The general color of the caterpillar upon the inferior surface, is a bluish 

 green, with obscure patches of black between the segments. Along the 

 middle of the dorsum, extends an obscure bluish band from the head 

 almost to the last segment. 



The caterpillars, at this stage, vary considerably in the time of moult- 

 ing. Some reach this period much sooner than others, at least two days 

 earlier, even in the same brood. It is the thrifty-looking caterpillars that 

 are thus favored. The ill-favored ones contrast quite remarkably with 

 the latter, in size, color "and markings. ' A number of caterpillars 

 was purposely confined to a bush of the red currant, whose leaves were 

 small and sickly-looking. They throve poorly, increasing but slowly in 

 size, while their more fortunate companions of the same brood fairly out- 

 stripped them in size and vigor, and actually passed through an entire 

 transformation in advance of them. At the start, they had no advantage 

 over their brethren ; all were favored alike. What could have wrought 

 the difference ? From the foregoing facts, the conclusion is irresistible 

 that nutrition had been the force at work ; the vigorous larvce, being 

 amply supplied with food of the very best quality, had rapidly added to 

 their size ; while their stunted companions, being supplied with plenty 

 of innutritious diet, had remained almost stationary. 



June 26th — The caterpillar has moulted' for the third time. Its length 



