FOREWORD. 



*' The importance o£ insects and ticks in relation to the spread of 

 disease in man and animals is now widely recognised. The malaria 

 parasite is conveyed to man by Anopheline mosquitoes, that of yellow 

 fever by Steyomu'ia fasciata, likewise a species of mosquito. Plague in man 

 and animals is in most instances conveyed Ijy fleas. The Trypanosomes 

 which cause sleeping sickness in man, and nagana in horses, cattle and 

 other animals, are conveyed from host to host by flies belonging to 

 the genus Glossina. African relapsing fever in man, a fatal disease in 

 poultry, red water and East Coast fever in cattle^ malignant jaundice in 

 dogs, biliary fever in horses, and heartwater in sheep and goats, are all 

 important diseases which are transmitted by different species of ticks. 



" Further, apart from disease in man and his cattle, there is the 

 widest field, at present almost unworked in Central Africa, for investi- 

 gation into the life-histories and habits of the numerous insects which 

 prey upon, and not infrequently annihilate, the crops upon which 

 humanity is largely dependent for its daily food. The success or failure 

 of the colonisation by white people of such a country as Uganda will 

 almost certainly be profoundly influenced by the insect enemies of 

 their crops, and it is- of the highest importance that the necessary 

 machinery for dealing with these enemies should be in working order, 

 or great loss and profound disappointment in the resources of the country 

 will ensue. The names of the insect pests are too numerous and too 

 well known to need mentioning, but it is worthy of remark that, while a 

 sound and efficient series of investigations has been established in South 

 Africa and in Egypt, similar enquiries in Central Africa, the northern 

 and southern portions of which are already being colonised, have yet to 

 be made. 



*' It is not too much to say that the cause of the almost complete 

 closure of Africa — lying as it does at the very foot of Europe — until 

 quite recent times, with the exception of a narrow littoral fringe, has 

 been the existence of disease- and death-carrying insects and ticks. 



** On the other hand, it must not be forgotten that many insects are 

 beneficial to man. More than one kind of ladybird, belonging to the 

 genera Vedalia and Orcus, introduced from Australia, has done much 

 to free the Californian orange trees from that destructive pest, the fluted 

 scale, Icert/a purcliasi, and Dr. Sharp states :— ' If anything were to 

 exterminate the enemies of Hemiptera, we ourselves should probably be 

 starved in the course of a few months.' If possible, it is important to 

 find out what insects are helpful to man in any new country before the 

 advent of large numbers of colonists upsets, as it is bound to do^ the 

 balance of power in the animal world. 



** It would thus seem most urgent, if we are to make our Central 

 African Colonies habitable and profitable, and, in a degree, healthy, for 



