BEHAVIOR OF SPIDERS AND OTHER INSECTS 415 



According to Wm. Moore (64), "One of the most important 

 and interesting problems in economic entomology is the role 

 played by ticks in the spread of ceitain diseases and how these 

 ticks may be destroyed." "In South Africa it is not one tick 

 and one disease which must be dealt with, but a number of 

 ticks producing a number of different diseases." The blue tick 

 causes Texas cattle fever and spirochaetosis ; the Bont tick 

 induces heart-water disease in sheep, goats, etc.; the dog tick 

 spread malignant jaundice among dogs; the brown tick trans- 

 mits East Coast fever and gall sickness to cattle and may trans- 

 mit Texas cattle fever; the Cape brown tick causes East Coast 

 fever ; the black pitted tick transmits East Coast fever and gall 

 sickness and may spread spirochaetosis; the red tick is a car- 

 rier of East Coast fever, gall sickness and the biliary fever of 

 horses. Moore discusses the life -histories of all of these ticks 

 and gives methods of combating them. What he considers the 

 most successful remedy is weekly dipping of the animals in a 

 sufficient amount of the following mixture: three pounds of 

 soft soap, one gallon of keiosene, four ponds of arsenite of soda, 

 and four hundred gallons of water. 



Frederick Knab (47) has well said: "The study of the role 

 of blood-sucking insects in the transmission ol diseases is a 

 recent one, and it is still to a large extent vague and chaotic. 

 Its teachings are not only built up largely on hastily collected 

 and faulty data, but they are replete with errors. Many of the 

 investigators not only have lacked the necessary knowledge of 

 biology, but the mastery of detail, along with a broader view, 

 which is eminently necessary in such work. Since the discovery 

 that certain blood-sucking insects are the secondary hosts of 

 pathogenic parasites, nearly every insect that sucks blood, 

 whether habitually 01 occasionally, has been suspected or con- 

 sidered a possible transmitter of disease. * * * In order to 

 be a potential transmitter of human blood-parasites, an insect 

 must be closely associated with man and noimally have oppor- 

 tunity to suck his blood. It is not sufficient that occasional 

 specimens bite man." There is "a certain class of blood-para- 

 sites and transmitters which apparently do not conform to the 

 principles laid down above. One class are the diseases trans- 

 mitted by ticks, where the parasites are directly transmitted 

 from the "tick host to its offspring, and where, for this reason, 



