32 



forwarded for identification to the British Museum (Natural History), 

 and should invariably be accompanied by all information necessary 

 for their determination, including a detailed description of the places 

 where they were unearthed. 



EMERGENCE OF THE PERFECT INSECT, OR IMAGO. On this subject 

 Austen remarks : " Although a Glossina escapes from its pupa-case 

 in precisely the same manner as any other Muscid fly, it may be of 

 interest to quote Stuhlmann's account of the emergence of the imago 

 of G. brevipalpis. ' The fly,' writes Stuhlmann, ' bursts off the cap 

 of the pupa-case, and protruding from the opening its cephalic vesicle,' 

 termed by Dipterists the ptilinum, ' forces its body-fluid into the 

 latter, so that its body becomes sufficiently thin to be able to creep 

 out of the puparium. Immediately after the insect has made its escape 

 the cephalic vesicle is retracted into the interior of the head and 

 never used again. In a short time the young fly draws air into its 

 tracheae, and, as a result of so doing, expands greatly ; the wings, 

 which until now have been folded, become spread out, and the abdomen 

 swells to twice or thrice its original size. The proboscis, which in the 

 pupa was directed backwards, is now stretched out in front, and the 

 chitin everywhere hardens. After from three to five hours it would 

 be impossible to tell from the appearance of the fly that it is still 

 quite young, and although on the first day reluctant to feed, it sucks 

 blood greedily on the second.' ' 



PARTHENOGENESIS. " It may be noted that there is some evidence 

 that parthenogenesis may in exceptional circumstances occur in 

 Glossina, since Stuhlmann states that at Amani on two occasions 

 virgin females of G. brevipalpis, bred in captivity, produced fully 

 developed larvae " (Austen). 



DURATION OF THE PUPAL STAGE. Thanks to investigations made in 

 Northern Rhodesia by Dr. Allan Kinghorn and Mr. LI. Lloyd, both 

 of the Luangwa Sleeping Sickness Commission, we are in possession of 

 a. certain amount of information as to the duration of the pupal period 

 in Glossina morsitans. 



The first observations covered only " a very short period, from the 

 middle of June to the middle of August." " The pupae," writes 

 Kinghorn (79), " as they were obtained, were placed in glass tubes and 

 left exposed to the laboratory air without any protection. In these 

 circumstances the time which has elapsed from the birth of the larva 

 to the escape of the imago has varied from 47 to 53 days." This, it 

 should be noted, was during the height of the dry season in Northern 

 Rhodesia. 



According to Lloyd (87), " Flies which emerged from pupae obtained 

 in October did so after a pupation period of 23 days, on an average. 

 The approximate mean temperature to which these pupae were exposed 

 was 85 F. The shortest pupation period observed was 21 days, 

 whilst the longest at this temperature was 25 days. Of the apparently 

 healthy pupae obtained during this period 49 per cent, died." 



In a subsequent paper (88), recording the results of his experience 

 with Glossina morsitans in the Luangwa Valley, Northern Rhodesia, 

 Lloyd writes : " The hot dry season has had a very deleterious effect 

 on the breeding of the flies, as shown not only by a reduction in the 

 numbers of pupae produced, but also by the subsequent death of a 



