﻿66 DR. J. W. SCOTT MACFIE — EXPERIMENTS AND 



12.54p.m. T. 41 Fly fell over and failed to get up again. Slight 



movements. 

 12.59 T. 41 After five minutes in this condition the fly was re- 



moved to a box at the temperature of the external 

 air. He did not, however, show any signs of life. 

 In the presence of moisture therefore it would appear that G. palpalis is able 

 to withstand exposure to sunlight for longer than in its absence. In this case 

 25 minutes at 41° C. (105*8° F.) elapsing before complete immobility was 

 induced, as compared with four minutes in the previous experiment (no. 5). A 

 further exposure of five minutes was however fatal. 



It was observed that the first effect on the flies of exposure to sunlight was 

 an increased activity. After a few minutes, however, they began to seek shade, 

 and became less active, until finally they were reduced to an inert condition from 

 which recovery, if it took place at all, was slow and often incomplete. 



When shaded from direct sunlight. 



The jars containing the flies in these experiments were protected from the 

 direct rays of the sun by a covering of thick brown paper. In some experiments 

 water was present in the jars, in others it was absent. 



(a.) In the absence of water. 



The following experiment will indicate the nature of the effects of a raising of 

 the temperature under these conditions : — 



No. 7.- — Male G. palpalis confined in a glass jar, wrapped in thick brown paper 

 so as to shade every part, together with a few twigs, but no water. Degree 

 of humidity of the atmosphere — 25. 

 2.24 p.m. T. 35° C. Fly introduced. Active. 

 Fly active. 

 Do. 

 Do. 

 Fly resting on the floor. 

 Fly active. 

 Do. 

 Do. 

 Do. 

 Fly resting on the floor. 

 Fly fell over " as if dead." On shaking the jar he 



got up on his legs again and moved about. 

 Fly resting on the floor. 



Fly fell over 4S as if dead," and failed to get up 

 again. There were, however, slight movements of 

 the legs. 

 Slight movements still. 



Do. do. 



No signs of life. 



2.27 



T. 38 



2.32 



T. 39 



2.35 



T. 40 



2.38 



T. 41 



2.43 



T. 41 



2.50 



T. 41-5 



2.55 



T. 41 



3.0 



T. 40 



3.5 



T. 40-5 



3.L0 



T. 41 



3.15 



T. 41 



3.20 



T. 41 



3.25 



T. 41 



3.30 



T. 41 



3.35 



T. 40 



