154 



Tsetse-flies, like all other Diptera, should, if possible, " always be 

 brought home alive in the glass-bottomed pill-boxes 1 .... to 

 which they are to be transferred on being captured in the net, and 

 should then be killed in the cyanide bottle or jar immediately before 

 being pinned. As soon as a fly is taken in the net by a dexterous 

 sweep, a sharp turn of the wrist must be given (following a smart 

 downward or lateral stroke in order to bring the fly to the end of the 

 net) in such a way that the end of the net containing the insect falls 

 over the rim and so makes a closed bag from which it cannot escape. 

 The end of the net can then be gathered up in the hand and the fly 

 forced into a still smaller space, in which it will not be difficult to get 

 it into a pill-box .... and then to slip on the lid .... 

 Flies may also be transferred direct from the net to the killing-bottle, 

 and so brought home dead ; but this method is not to be recommended, 

 since prolonged exposure to the effects of cyanide of potassium is apt 

 to injure the specimens, the ultimate condition of which, when thus 

 treated, is rarely so satisfactory as if they had been brought home 

 alive in pill-boxes. If, however, it is necessary for any reason to 

 dispense with pill-boxes .... and to use the killing-bottle in 

 the open, a little crumpled tissue-paper should be placed inside it ; 

 this affords a lodgement for the specimens, and so lessens the risk of 

 their being injured by rolling about .... It is always advisable 

 when out collecting to carry a killing-bottle for use in case of need, 

 in the event of the supply of pill-boxes .... running short." 



METHOD OF COLLECTING TSETSE-FLIES. When it is desired to study 

 the seasonal distribution of the Tsetse-flies in a given region, to discover 

 what species of Glossina occur there or to learn the proportion of the 

 sexes, or, again, when the object is to catch living females to be used in 

 laboratory experiments, it is necessary to engage a certain number of 

 natives, whom it is customary to term "fly-boys," and, after having 

 trained them to recognise and catch these insects, to send them out 

 as collectors into the different districts. 



Writing on this subject in connection with the Ilorin Province of 

 Northern Nigeria, Dr. J. W. Scott Macfie observes (94) : " Of the 

 large number of natives who passed through my hands most were 

 found to be of little use, because, although they were able to catch 

 specimens where they were plentiful, they lacked the perseverance, or 

 some peculiar personal allurement, necessary to procure them in less 

 likely spots. Eventually, however, I was able to select three or four 

 who showed some aptitude and a degree of discrimination, and by 

 them were made most of the collections on which this report is based. 

 I was also fortunate enough to obtain the co-operation of the Adminis- 

 trative Officers, who interested themselves in the work and not only 

 furnished me with valuable information, but also consented to take 

 collectors with them when on tour in their divisions, thus enabling 

 me to obtain insects even from the most remote corners of the 

 province." 



In this way Dr. Macfie was able to obtain no fewer than 612 collec- 

 tions, " from more than 500 different localities," of which he gives 

 an alphabetical list at the end of his paper, besides so far as possible 

 showing them on a map by means of Dr. J. J. Simpson's system of 

 conventional signs (see below, p. 162). " The list," writes Dr. Macfie, 



1 The lids of these should be pierced with a few small holes, to admit air. 



