198 



I September, 1912. 



SANGUINARY INSECTS OF ZANZIBAR. 



If Zanzibar is fortunate in the comparative paucity of its pests of 

 economic plants, it appears to be well provided with blood-sucking insects 

 of various kinds. As the author of this Leaflet (No. 2, " On the Blood- 

 sucking Arthropods of Zanzibar harmful to Man or Stock," by W. M. 

 Aders) remarks :— " The last twenty years have shown that these insects 

 have a great significance as carriers of disease to man and domestic 

 animals." 



Of the various insects enumerated, by far the greater number are 

 the two-winged flies (Diptera). It is remarkable that nearly all the 

 insects provocative of disease come under this order, which includes 

 Mosquitoes or Cuhcidce (responsible for Malarial and Yellow Fever), 

 ' Gad-Flies' or Tabamdce (believed to be concerned in the communication 

 of certain diseases of horses and cattle), ' Sand-Flies ' of the genus 

 Pldebotomus (agents in the dissemination of ' Papataci' Fever in Malta), 

 ' Stable-Flies ' of the genus Stomoxys (suspected of communicating 'Surrah' 

 disease of horses), ' Tsetse Flies ' or Glossina (agents in the transmission 

 of the dreaded 'Sleeping Sickness' of Central Africa), 'Bot Flies' or 

 (Estridce (the cause of various tumours in cattle), and— last, but not least 

 — the pestilential ' House Fly ' (Musca domestica), which has been proved 

 to be a prolific agent in the distribution of the germs of Typhoid Fever 

 and other diseases of an allied nature. 



Fleas (Siphonaptera), one or more species of which are concerned in 

 the transmission of Bubonic Plague, are very closely allied to the Diptera 

 and were formerly included in that Order. 



The remaining blood-sucking insects belong to the order Hemiptera, 

 as exemplified by the ' Bed-bugs ' (Cimicidce) and the ' Cone-nosed Bugs ' 

 (Conorhinus). A species of this latter genus has been shown to transmit 

 a Trypanosome responsible for a serious and often fatal disease, in Brazil. 

 Conorhinus rubrofasciatus occurs commonly in Ceylon, and has the 

 sanguinary habits of its race (vide ' Trop. Agricult.', April 1910, p. 323), 

 but no disease has— as yet— been traced to bites of our local species. 



Ticks (Ixodidce) are not true insects, though rightly included under the 

 more comprehensive title of Arthropoda. They are well known agents in 

 the transmission of several important diseases of cattle in South Africa. 



E. E. G. 



CEARA RUBBER. 



Der Tropenflanzer for April 1912, p. 208, contains an abstract of an 

 account of work carried out with Manihot Glaziovii in German East 

 Africa, in which the results of the investigation permit it to be gathered 

 that the branches of this tree contain quite 121 per cent, more rubber 

 than the corresponding parts of a stem belonging to a tree which has 

 branched high up, but that the cost of tapping is at least 30 per cent, 

 greater. It is further admitted that no more favourable results are pro- 

 duced in cases where more branching exists than is found in the 

 average tree. 



