﻿12.15 



T. 



10 



12.35 



T. 



10 



12.40 



T. 



10 



12.45 



T. 



9-5 



12.55 



T. 



10 



1.5 



T. 



10 



1.15 



T. 



10 



1.20 



T. 



7 



1.25 



T. 



7 



OBSERVATIONS UPON GLOSSINA PALPALIS. 63 



An experiment was then made with a recently captured female G. palpalis : — 



No. 2. — Female G. palpalis. Temperature of the external air — 



33° C. (91*4° F.). 



12.5 p.m. T. 10° C. Fly introduced. She at once settled on the floor of 



the chamber. 

 Fly has not moved at all. 



Do. 

 Position unchanged. Stroking wings with hind legs. 

 Do. 

 Do. 



Do. Stroking wings. 



Do. 

 Do. 

 Do. 



The fly was then removed from the cold chamber, and rapidly recovered her 

 activity. 



The female G. palpalis is therefore able to withstand exposure for an hour and 

 twenty minutes to a temperature ranging from 10°-7° C. (50°-44 , 5° F.) without 

 harm. This is a degree of cold to which she would never be exposed naturally 

 at Zungeru, where the minimum temperature recorded in 1910 was 13*8° C. 



In the case of the male used in the following experiment, twenty minutes 

 exposure to a temperature falling from 16° to 7° C. (60*8° to 44*5° F.) resulted in 

 reducing the fly to an inert condition, from which, however, he recovered rapidly 

 on being removed from the cold chamber. 



No. 3. — Male G. palpalis. 



11.40 a.m. T. 16° C. Fly introduced. Settled on a twig. 



11.45 T. 10 Fly has not moved. 



11.50 T. 9 Do. 



11.52 T. 8 Do. Proboscis depressed. 



11.55 T. 7-6 Do. 



12.0 T. 7 Fly fell off the twig " as if dead." 



At once removed to the external air. Recovered activity rapidly. 



Temperatures sufficiently low to render the flies inert are not therefore neces- 

 sarily fatal. In one case a fly was allowed to remain in this condition for five 

 minutes at a temperature ranging from 8°-5*5° C. (46*4°-42° F.), and recovered 

 completely within two minutes after being removed to the temperature of the 

 external air which was at the time 27° C. 



That G. palpalis can resist relatively low temperatures the following experiment 

 proves. It also indicates the probable limit of low temperature, beyond which 

 recovery does not take place ; as the fly, after having been exposed to a temper- 

 ature at one time as low as 2*5° C. (36*5° F.), only recovered partially on being 

 removed from the cold chamber, and subsequently died within twelve hours. 



