﻿OBSEKVATIONS UPON GLOSSINA PALPALIS. 65 



that a distinction must be made between shade temperatures, and those attained 

 by direct exposure to sunshine. In the following experiments tsetse-flies were 

 exposed to the various temperatures in glass jars fitted with a thermometer. 

 Twigs on which the flies might settle were always present. It may be stated at 

 once that the flies appeared to be much more susceptible to a raising of the 

 temperature than they were found to be to a lowering. In the experiment 

 described above as No. 4, the fly withstood for some time a lowering of the 

 temperature of 23*5° C. (viz., from 26° C. to 2'5° C), whereas in experiment 

 No. 8, a raising of the temperature only 10° C. (viz., from 34° C, the temperature 

 of the external air at the time of the experiment, to 43°-44° C.) was more than 

 could be endured. 



In direct sunlight. 



(a.) In the absence of water. 

 In these experiments tsetse-flies were exposed in glass jars to the direct rays of 

 the sun. Small twigs were included in the jars, but no water. The following 

 experiment will indicate the nature of the effects observed. 



No. 5. — Male G. palpalis. Degree of humidity of the atmosphere — 25. 

 Fly exposed to direct sunlight. 

 Fly active. 



Do. 

 Fly fell to the floor and rolled over " as if dead." 

 After five minutes in this condition and at this 

 temperature he was removed to a box at the tem- 

 perature of the external air. 



absence of moisture, is therefore rapidly fatal to 

 G. palpalis ; in this case five minutes exposure at 41° C. having proved fatal. 



(b.) In the presence of water. 

 The present experiments only differed from those described above in the fact 

 that water was present in the jars. The following are the notes of one 

 experiment : — 

 No. 6. Male G. palpalis. Water and twigs in the jar. The temperature of 

 the external air was 31*5° C. (88*7° F.). 

 Fly introduced. Active. 

 Fly active. 



Do. 

 Fly active ; looking for shade. 



Do. do. 



Fly fell over on to his side, but got up again. Less 



active. 

 Less active. 



Fly fell over again, but got up with difficulty. 

 Fly crawling about looking for shade, and constantly 

 falling over and getting up again with increasing 

 difficulty. 



23527 E 



2.4 p 



.m, 



T. 34° C. 



2.6 





T. 38 



2.7 





T. 40 



2.8 





T. 41 



2.13 





— 



$o recovery 



took place. 



direct 



sunli^ 



ght, in the 



12.29 p.m. 



T. 40° C 



12.32 



T. 41 



12.35 



T. 41 



12.37 



T. 41 



12.40 



T. 41 



12.43 



T. 41 



12.44 



T. 41 



12.45 



T. 42 



12.48 



T. 41 



