DE. J. KIEK ON THE TSETSE ELY OE TROPICAL AFRICA. 151 



in a comraunication made to tlie Entomological Society *. Here 

 we find noticed almost every point which has yet been brought 

 forward. It is stated that the fly is strictly localized, and not 

 known to shift its ground ; that during the heat of the day it is 

 active, but does not bite by night, and that the natives then pass 

 cattle without loss through " fly country." Mr. Oswell believes 

 that three or four flies are sufiicient to kill a full-grown ox. 

 Similar appearances were found by him in the bodies of twenty 

 oxen which died after being bitten. These were a watery and 

 wasted state of the flesh ; stomach and intestines healthy ; heart, 

 liver, and lungs — sometimes all, invariably one— diseased, the sub- 

 stance of the heart in particular being soft ; the blood diminished 

 in quantity, albuminous and thick, not staining the hands when 

 plunged into it, 



Mr. Oswell states that while man, the goat, and wild animals 

 are bitten with impunity, as also calves sucking milk, other do- 

 mestic animals perish ; the symptoms being swelling of the eye- 

 lids, a watery discharge from the eyes, and considerable enlarge- 

 ment of the sublingual glands. 



Dr. Livingstone, who accompanied Messrs. Oswell and Murray 

 to Lake Ngami, and with the former experienced the fly on their 

 way to the Makalolo country, makes frequent mention of the 

 " Tsetse " in his ' Missionary Travels.' He amplifies and con- 

 firms what had been before stated, adding much to our know- 

 ledge of its habits and distribution. He mentions that the ass is 

 not afi"ected by the bite ; and although the sucking calf lives, the 

 dog fed on milk dies. 



On one occasion Dr. Livingstone suffered a loss of forty-three 

 of his oxen, and believes that not a score of flies were ever upon 

 them. As an instance of the sharply-defined habitat of this fly, 

 he gives that of the " Chobe," a stream fifty yards wide, on the 

 north bank of which his cattle grazed in safety on pastures free 

 from fly, while the south side was infested and had proved fatal, 

 and this while the " Tsetse " was seen adhering to flesh carried 

 across the stream in canoes. 



Dr. Livingstone's most important observation is the connexion 

 between the fly and large game, especially the buffalo and 

 elephant, and its absence from parts where these do not exist, 

 pointing to a possible means of ridding a country from this curse. 



Other travellers in the south have encountered this fly, and all 

 bring home the same tale. 



* Transactions of the Entomological Society of London. 



12* 



