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NOTES ON GLOSSINA MORSITANS IN NORTHERN 



RHODESIA. 



By Ll. Lloyd, B.Sc. 



Entomologist to the Luangwa Sleeping Sickness Commission. 



Temperature in relation to Glossina morsitans. 



Roubaud has recently recorded (cf. Sleeping Sickn. Bull., Ill, p. 419) that in 

 West Africa G. morsitans is intolerant of high temperatures, as he has found 

 that specimens exposed to 40° C. (104° F.) died within an hour. This species is 

 however adapted to withstand such a temperature in the Luangwa Valley ; for 

 during the hot months of October and November the shade thermometer 

 frequently registers from 106° to 108° F., seemingly without any ill results to 

 the tsetses. 



Duration of the pupal period of G. morsitans. 



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 % died. 



The Dissection of the Salivary Glands of G-lossina. 



Workers on the transmission of trypanosomes by various species of Glossina 

 have hitherto been unable to agree as to the part played by the salivary glands 

 in the process. It is of importance therefore that some method of removing the 

 glands be adopted in which the risk of contamination by gut-contents would be 

 reduced to a minimum. The usual method employed hitherto has been to remove 

 the entire viscera by means of pressure on the abdomen, after either the removal 

 of the last segment, or the severance of the abdomen from the thorax. These 

 methods are open to the criticism that the gut, especially if it contains much 

 blood, is liable to rupture ; that the glands are liable to lesion ; and that it is 

 very difficult to dissect them free from fat body and gut. 



The complete salivary glands may be obtained without risk of rupture of the 

 gut by the following method. G. morsitans has been used in the dissections. 

 The fly is held firmly in the hand and a longitudinal incision is made in the 

 median dorsal line of the thorax from the neck to the abdomen. The insect is 

 then immersed in normal salt solution and incisions are made along the transverse 

 groove of the thorax from the median incision almost to the bases of the legs. 

 The strong muscles in the thorax which run in a longitudinal direction should 

 also be severed. A needle is now placed in the anterior end of the longitudinal 

 incision, and another in the posterior end. A gentle longitudinal pull applied to 

 the fly by these needles causes the remainder of the thorax to break across. The 

 alimentary canal breaks between the pharynx and proventriculus, while the 

 salivary glands are drawn out of the abdomen quite free from fat body and with 



