ABSTRACT
The present study constitutes an attempt to correlate the processes of insect metamorphosis with certain of the more obvious metabolic changes characteristic of larval and pupal life. Throughout this work it has become obvious that the chemical constitution of different batches of larvae or pupae may be very different although all composed of individuals of the same age. One particular instance of this may be cited at the outset. Two batches of larvae, A and B, were reared under almost identical conditions, A being from slightly earlier ovipositions and reaching maturity about two days before B. Both were reared at a somewhat low temperature until nearly mature and the only differences between the two batches were that the higher temperature would commence nearer maturity for batch A than for batch B, and that the sand in which A were reared was somewhat more moist than was the case for larvae B. Both batches pupated very slowly. In each case samples of the body fluid were taken on the day when the majority of the larvae had evacuated the gut, and again two days later. Not only was there marked differences in the physical properties of the body fluids but there was also a difference in colour: the fluid of specimens A being yellow and deeply pigmented, whereas that of B had the normal greenish tinge and was less pigmented.
