NO. l8 SENSE ORGANS OF COLEOPTERA — McINDOO 27 



attractatit. In the course of random movements certain other insects 

 may come upon sugar, for example, which holds them after they 

 have touched it. In this case, Campbell says that sugar might be called 

 a true " arrestant." If insects have true senses of smell and taste, 

 an attractant then attracts through the sense of smell and an arrestant 

 arrests through the sense of taste. 



Since entomologists already know much of the following informa- 

 tion, only the more important references consulted will be cited here. 

 The substances inodorous or slightly odorous to us, which have been 

 found repulsive to insects, may be briefly discussed as deterrents. 

 Whitewash may be considered the first deterrent used. White- 

 washing the bases of fruit trees has been practiced for years. It is 

 still questionable whether such a practice is of any real economic 

 importance, but its advocates claim that the lime in it has a tendency 

 to drive away noxious insects and may be slightly injurious to in- 

 sect eggs. The most improved and best mixture of whitewash, as 

 recently recommended in France, consists of lime, calcium arsenate, 

 lime sulphur, and water. In this case the lime might act as a deterrent 

 and the lime sulphur, which has a strong disagreeable odor, as a 

 repellent. One of the most efficient deterrents used in the United 

 States is air-slaked lime, which is employed extensively for dusting 

 melons and cucumbers to prevent the attacks of the striped cucumber 

 beetle. It is also said to prevent injury to stored beans by the bean 

 weevil. In Germany a mixture of white sand and hydrated lime has 

 recently been used to deter flea-beetles. Paints, particularly white- 

 lead paint, are recommended for preventing boring beetles from 

 entering wounds on fruit trees. The coat of paint covering the fresh 

 wound preserves the wood and also acts as a mechanical barrier to 

 the beetles. Lead arsenate, when sprayed or dusted on foliage, deters 

 a number of insects, including the Japanese beetle, western cabbage 

 flea-beetle, desert corn flea-beetle, and striped cucumber beetle. Most 

 of the arsenicals deter the Mexican bean beetle. Bordeaux mixture 

 sprayed on the leaves of eggplant and potatoes deters flea-beetles and 

 the potato leaf hopper, which causes the disease called " hoppcrburn." 



In regard to repellents used against beetles, the first ones used 

 were probably decoctions of certain poisonous plants. As early as 

 1848 leather waste from tanneries, when put among plants in Germany, 

 was found to be a repellent against flea-beetles, and more recently in 

 France sawdust coated with coal tar when placed among the plants 

 repelled these insects. The most successful repellent used against 

 these tiny insects and the striped cucumber beetle in the United States 



