Open Access

Charles Gordon Hewitt

• During recent years our knowledge of the biology and distribution of the ticks has greatly increased owing to the discovery of the economic importance of this group as carriers of certain serious diseases to man and domesticated animals. In North America we have the North American Fever Tick Margaropus annulatus Say, the well known disseminator of splenitic or Texas fever of cattle, which is credited with an annual loss of about fifty million dollars to the cattle industry of the southern States, and the Rocky Mountain Spotted Fever Tick, Dermacentor venuslus, the responsible agent for this human disease which has a high rate of mortality. With tlie exception of the work of Dr. Seymour Hadwen, Assistant Pathologist of the Health of Animals Brancl-i of the Dominion Department of Agriculture and, to a lesser extent, of myself, no serious attempt has been made to study the ticks occurring in Canada. The present account has been prepared with a view to bringing together the hitherto unpublished results of rny own work, and those of Hadwen, together with such scattered references as I have been able to find. It is hoped that this information will constitute a basis for further work, and that the comparative meagreness of the records will stimulate others to add to our knowledge of a group which offers problems of unusual interest. Except where it is otherwise stated the records in the following account are mine. Hadwen has studied the life-histories of a number of the species and in such cases his results have been given in full or summarized.