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brown paper. In some experiments water was present in the jars, in 

 others it was absent." 



The conclusions deduced by the author from the whole series of 

 experiments are stated as follows : 



"1. Glossina palpalis is able to withstand a lowering of the tem- 

 perature to 10-7 C. 



" 2 Direct sunlight is rapidly fatal to G. palpalis. 

 " 3. When shaded, exposure for one hour to a temperature of 

 40-41C. is fatal to the male G. palpalis. Higher 

 temperatures are more rapidly fatal. 



"4. The presence of water enables G. palpalis to withstand for a 

 longer period the action of direct sunlight, and perhaps of 

 a shade temperature of 40-41 C. 



"It is probable, therefore, that the diminution in the number of 

 tsetse-flies during the dry season, and their limitation to the bush 

 along the river banks, is due not so much to the low temperatures 

 registered at nights during this season, nor to the high temperatures 

 occurring during the days, as to the dryness of the atmosphere and the 

 burnt-up condition of the country." 



MODE OF DEATH. On this subject Dr. Macfie writes : " A note 

 should perhaps be included here on the manner of death of the flies 

 used in the experiments. When an exposure was nearing a fatal 

 termination the flies became less active, and would presently settle on 

 a twig, or on the floor of the jars in which they were contained, in a 

 lethargic condition, being with difficulty persuaded to move, even 

 when touched with the end of a probe. A little later they would 

 fall over on to their backs with their legs pointing up into the air, and 

 their probosces projecting forwards. In this state they might remain 

 for a considerable time. At first, when disturbed, they would be able 

 to struggle to their feet, only to fall over on to their backs again in a 

 few moments. Later, they were only able to respond by movements, 

 more or less free, of the legs and proboscis. In this condition, which 

 in the notes of my experiments I have described by the expression 

 ' as if dead/ they remained until death took place, the movements 

 gradually becoming less perceptible. In exposures to an increased 

 temperature the flies sometimes spread out their wings convulsively 

 j ust before death. After death the proboscis was generally depressed. 



THE INFLUENCE OF COLOURS. The following statement is made by 

 Dr. Macfie with reference to the influence of colour on Glossina palpalis. 

 " Having previously ascertained that, in the case of the male G. 

 palpalis confined in a glass jar without water at a temperature of 

 40-41C. (104-105-8 F.), whereas exposure to direct sunlight was 

 rapidly fatal, a similar result was only produced after an hour's exposure 

 if the jar was shaded from the direct rays by a covering of thick brown 

 paper, some experiments were carried out to determine whether under 

 similar conditions different colours would produce different results. 

 Male G. palpalis flies were therefore exposed to a temperature of 

 40-41 C. in glass jars shaded respectively with red, green, blue and 

 yellow paper covers. No water was present in the jars. In the case 

 of the red, yellow and blue covers, after an hour's exposure the flies 

 seemed to be none the worse, and remained very active throughout 

 the experiments. In the case of green, however, after an hour's 

 exposure the fly was showing evident signs of distress, and by continuing 

 the experiment for a further 18 minutes he was killed .... Bearing 



