Insect development. IV. External morphology of grasshopper embryos of known age and with a known temperature history

Abstract

Abstract Eggs of Melanoplus differentialis, a grasshopper, secured immediately after they had been laid, were placed in a water bath kept at 25°C, and allowed to develop for definite periods. After fixation, the embryos were dissected out of the eggs and drawn. Large numbers of eggs were examined in order to determine the degree of variation under specific conditions. For the stages following revolution, eggs were used in which ‘hibernation’ had been prevented by exposure to low temperatures.