NO. 2337. NEW AMERICAN FOSSIL INSECTS— COCKERELL. 309 



makes it easy to distinguish tsetse flies in the field from various other 

 blood-sucking Diptera. The venation of the wings is unique, the 

 fourth vein (so-called) being abruptly bent or looped up in the 

 middle, where the anterior cross- vein meets it. The mode of repro- 

 duction is also very remarkable, since the females lay no eggs, but 

 each one produces a single full-grown larva, which almost imme- 

 diately becomes a pupa. 



Thus the tsetse flies Avould attract the attention of entomologists on 

 account of their structure and habits alone, were they of no special 

 importance to mankind in general. Thanks to the labors of Sir 

 David Bruce and many others in tropical Africa, we now know that 

 various species of Glossina are carriers of parasitic Protozoa of the 

 genus Trypanosoma^ which cause fatal diseases in man and animals. 

 The nagana disease of cattle, due to a parasite carried by Glossina 

 morsitans^ is absolutely ruinous to the stock interests in certain dis- 

 tricts. The parasite exists also in the wild hoofed animals, which do 

 not become diseased, but serve as reservoirs from which domestic 

 cattle and horses may be infected, provided the proper fly is present. 

 This fact has led to an agitation in some quarters for the destruction 

 of the larger wild animals, such as zebras and antelopes ; but it is to 

 be hoped that better means will be found to avoid the spread of the 

 disease. Even more serious is the sleeping sickness of man, due to a 

 trypanosome conveyed principally, at least, by Glossina palpalis. 

 Owing to the opening up of trade routes through tropical Africa, this 

 disease has spread far beyond its original area and has destroyed 

 countless numbers of human beings. Medical men have labored 

 incessantly, and no expense has been spared to find remedies and 

 means of prevention. But while the white man is now able to take 

 care of himself in nearly every case, it is an enormous problem to 

 protect the native people all over central Africa. Up to the present 

 time 17 species and 4 recognizable varieties of tsetse flies are known 

 from Africa. The following chronological table shows when and by 

 whom they were described. Synonyms are omitted. 



1830. longipalpis Wiedemann; palpalis Robineau-Desvoidy. 



1849. fusca Walker. 



1850. tachinoides Westwood; morsitans Westwood; tahaniformis 

 Westwood. 



1891. pallicera Bigot. 

 1895. longipennis Corti. 

 1903. pallidipes Austen. 

 1905. palpalis wellmani Austen. 



1910. fuscipes Newstead; morsitans submorsitans Newstead; nigro- 

 fusca Newstead ; hrevipalpis Newstead. 



1911. caZip'meft Austen ; fuscijjleuris Austen; medicorum Austen. 



1912. avsteni Newstead; ziemanni Griinberg. 



1913. morsitans pallida Shircore; morsitans paradoxa Shircore. 



