. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PRESSURE AND INSECT FLIGHT 117 reflex. Later, D. virilis Sturtevant was also used. In working with D. repleta, individuals were selected at random from a wild population that maintained itself in the animal rooms and were used without regard to age or sex, since we were unaware at the time that frequency of wingbeat is determined to some extent by these variables. This defect in technique has contributed to the scatter in the data, and was avoided in the studies with D. virilis, which were grown under standard conditions at
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. PRESSURE AND INSECT FLIGHT 117 reflex. Later, D. virilis Sturtevant was also used. In working with D. repleta, individuals were selected at random from a wild population that maintained itself in the animal rooms and were used without regard to age or sex, since we were unaware at the time that frequency of wingbeat is determined to some extent by these variables. This defect in technique has contributed to the scatter in the data, and was avoided in the studies with D. virilis, which were grown under standard conditions at 25 degrees C. and isolated daily on emergence. The apparatus in which wingbeat frequency was measured is a simplified version of the flight chamber described by Williams and Chadwick (1943), and has been diagrammed in Figure 1. It consists of a glass pressure chamber whose tempera- ture was controlled either by circulation of water through a surrounding jacket or by immersion in a constant temperature bath. Provisions were made for clamping. TO VACUUM PUMP TO MANOMETER AND GAS TANKS FIGURE 1. Apparatus for measurement of wingbeat frequency at various pressures. For explanation see text. rubber stoppers, one of which held a thermometer, into the ends of the pressure chamber, while glass tubes, passing through the stoppers, allowed gas mixtures of known composition to be circulated. These mixtures were made up at high pressure in commercial gas cylinders and analyzed before use. At each change of gas mixture the chamber was washed thor- oughly with the succeeding mixture. Pressure within the chamber wras varied by the addition of compressed gases or by means of a vacuum pump. A pressure gauge and mercury manometer, measuring up to 5 atmospheres, were sealed into the gas lines and permitted a continuous check on the pressure within the experimental chamber. Relative humidity was held at or near 100 per cent by placing a few drops of water within the chamber and by bubbling the gas
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
