RELATIVE SUSCEPTIBILITY TO ARSENIC IN SUCCESSIVE INSTARS OF THE SILKWORM
The susceptibility of the silkworm to arsenic decreases during its larval development. Relative susceptibility may be expressed numerically as a ratio of areas under dosage-effect curves.
METABOLISM DURING EMBRYONIC AND METAMORPHIC DEVELOPMENT OF INSECTS
1. For species of insects that deposit their eggs on foliage, as Leptinotarsa decemlineata, Crioceris asparagi, and Anasa tristis, the rates of metabolism as measured by the CO(2) output or the oxygen intake indicate, during embryonic development, a short formative period, followed by a very active extended growth. Those species that deposit their eggs in the soil, as Cotinis nitida and Popillia japonica, show that the formative period is greatly extended and the growth period similarly lengthened. 2. It has been shown from metabolism experiments that intensive histolysis occurs during the prepupal period and becomes less intensive during pupal development. 3. Metabolism experiments show a greater amount of energy change during embryonic development as compared to the energy developed during metamorphosis. This is shown by the greater CO(2) output and by the oxygen intake. 4. Low respiratory quotients, varying from 0.42 to 0.71, have been obtained during the embryonic and pupal development of insects, resembling similar low quotients obtained with hibernating forms. 5. Changes from a neutral to an acid reaction (pH 6.8 to 5.9) have been observed to take place in some species during prepupal and early pupal development. As metamorphosis is completed a converse change occurs (pH 5.9 to 6.8). Changes in pH from an acid to neutral reaction were also observed to take place in some species, as Cotinis nitida and Hylemyia cilicrura, during embryonic development.
Lehrbuch der vergleichenden Entwicklungsgeschichte der wirbellosen Thiere
EMBRYOLOGISTS who are already acquainted with the “Lehrbuch der vergleichenden Entwicklungsgeschichte der wirbellosen Thiere” —and what embryologist is not?—will welcome with delight the appearance of these further instalments of the “Allgemeiner Theil.” No pains have been spared in the preparation of these two volumes, and authors and publishers alike are to be congratulated on their achievement.Lehrbuch der vergleichenden Entwicklungsgeschichte der wirbellosen Thiere.By Prof. E. Korschelt Prof. K. Heider. Erste und Zweite Auflage, Allgemeiner Theil, Vierte Lieferung. Erste Hälfte. Pp. 167–470. Price 7.50 marks. Zweite Hälfte. Pp. 471–896. Price 11 marks. (Jena: Gustav Fischer, 1910.)