24 Guide to Insects and Ticks 



body, and is continued forwards into a filament or flagelliim. In 

 an allied genus, Triipanoplasma, there is a fiagellum at each end of 

 the body. 



Although many forms of trypanosomes are spread from one 

 vertebrate host to another by tsetse-flies, some are spread by other 

 blood-sucking invertebrates, such as gnats, fleas, leeches, etc. ; the 

 trypanosomes that are found in skates and similar fishes, for 

 instance, are known to be conveyed by marine leeches. In the 

 case is shown a specimen of an African fly, Hippohosca rufipes von 

 Olfers, allied to the forest-fly of Britain, Hippohosca equina Linn, 

 (see enlarged photograph ( x 6) below the glass plate), and respon- 

 sible for the spread of the blood-parasite Trypanosoma thcileri 

 Bruce, causing gall-sickness among cattle in the Transvaal. 



Other trypanosomes of interest in connection with disease are 

 T. cquinum Vosges, causing " mal de caderas " of horses in South 

 America, T. evansi Steel, causing surra of horses and cattle in 

 India, and T. cquiperdum Doflein, causing dourine in horses in the 

 countries around the Mediterranean Sea, and T. cruzi Chagas, the 

 cause of the fatal disease barbeiro in man, particularly children, 

 in South America, and conveyed by a hemipterous insect or bug, 

 Lamus mcgistus Burmeister, more than an inch in length. 



In the large case that stands at the entrance to Bay I, near 

 the bust of Sir William Flower, is shown a selection of tsetse- 

 flies, together with enlarged coloured drawings ( x 6), and maps 

 showing the distribution of the several species. Tsetse-flies may 

 be said to be African insects, although one species is met with in 

 south-western Arabia, and in former times tsetse-flies existed in 

 North America. 



The first examples shown are those of Glossina palpalis 

 Eob.-Desv. (fig. 6) of West and Central Africa, the principal 

 disseminator of Trjipanosoma (lamhicnsc Dutton, causing sleeping 

 sickness in man. These tsetse-flies exist only in shady places, 

 and haunt the margins of lakes and water-courses where the 

 banks are covered with vegetation. Specimens are shown of 

 young and full-grown larvae (in the small glass vessel of alcohol), 

 and of pupae, together with some of the soil in which they were 

 found (in the glass-topped box). Glossina palpalis, like other 

 tsetse-flies, l)ut unUke the vast majority of flies in general, does 

 not lay eggs ; the female produces at intervals a single larva, or 

 maggot, which is retained within the body of the mother until full 



