. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 26 I. E. GRAY for a few days seeking a place to pupate. Entrance upon the prepupal stadium is gradual and is determined with difficulty. As soon, however, as the prepupae be- come sluggish and take on their characteristic white, fatty appearance, they can then be readily distinguished from the active, bluish larvae that are still feeding. The prepupal stage lasts 5 to 6 days. On hatching from the egg the larvae vary in length between mm. and mm. and weigh between nig. and mg. Little or no food is taken for
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 26 I. E. GRAY for a few days seeking a place to pupate. Entrance upon the prepupal stadium is gradual and is determined with difficulty. As soon, however, as the prepupae be- come sluggish and take on their characteristic white, fatty appearance, they can then be readily distinguished from the active, bluish larvae that are still feeding. The prepupal stage lasts 5 to 6 days. On hatching from the egg the larvae vary in length between mm. and mm. and weigh between nig. and mg. Little or no food is taken for the first day or so, but after feeding is well under way—in 24 to 36 hours—the color changes from white to bluish and the increase in size and weight is rapid. There is great individual variation, but the weight of a larva may increase to as much as 1800- 1600. FIGURE 3. Changes in weight of Passahis coniutus from larva to adult. I, II, III, the three larval instars; pp, beginning of prepupal stage; p, beginning of pupal stage; na, newly transformed adult. 140 mg. by the end of the first instar, 400 mgs. by the end of the second instar, and 2000 mgs. by the end of the third instar. Thus the weight may increase a thousand- fold in less than 2 months. The weight falls slightly after the late third instar larvae cease feeding and enter the prepupal stage; it rises slightly just before pupation begins; and again falls off, this time abruptly, on emergence of the adult. The weight of the adult is about five-sixths that of the greatest weight of the larva. Individual weight records were kept on many larvae raised in the laboratory and carried through to adulthood. A typical weight curve is given in Figure 3. Among the adults, as in all other stages, great individual variation in weight occurs. There is no sexual dimorphism, but the average female is larger and about 12 per cent heavier than the average male. The average weight of 27 old (not newly. Please note that these images
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
