33 



large proportion of these. In the hotter months great difficulty was 

 experienced in keeping the stock flies alive." 



Below is reproduced a table, in which Mr. Lloyd summarises the 

 observations made on all the pupae produced, in the course of his 

 investigations in the Luangwa Valley, from 27th June 1911 to 15th 

 March 1912. 



Table showing the duration of the pupation period of G. morsitans 

 at various temperatures (altitude 2,000 ft.). 



* Approximate. 



Under the heading " Breeding," Mr. Lloyd writes : " Abortions 

 were most numerous during September and October, while in the 

 cooler months there were not many. The number of stock flies was 

 roughly constant, the small number of pupae obtained during September 

 being due to the raid of ants . . . [an incursion of driver-ants, 

 which raided the laboratory and killed every fly in the bottles]. Flies 

 freshly caught do not breed so well as those which are accustomed to 



captivity The table shows that as the temperature rose 



from 67 to 85 the duration of the pupal life was reduced from 



ol to 23 days Without direct experiment it would 



be impossible to estimate the relative influence of temperature and 

 humidity. Since, however, the humidity of the air to which the 

 pupae of November 1-15 were exposed was greater than that 

 during the pupation period of the October groups, it would appear to 

 be the high temperature rather than the low relative humidity that 

 caused the death of the pupae." 



Under laboratory conditions in Italian Somaliland, the average 

 length of the pupal stage of G. pallidipes, according to Croveri (35), is 

 28 days. Some pupae of this species, kept in a room in which the 

 afternoon temperature exceeded 85 F., gave rise to adults in a shorter 

 time. 



(5979) c 



