TROPISMS AND SENSE ORGANS OF COLEOPTERA 



By N. B. McINDOO 



senior entomologist, peciduous-fruft insect investigations, bureau of 

 entomology, u. s. department of agriculture 



CONTENTS 



PAGE 



Introduction 2 



A. Tropisms 3 



I. Phototaxis, geotaxis, and thigmotaxis 3 



1. Review of literature 3 



(a) General remarks 3 



(b) Light traps for beetles 5 



2. Original work on Mexican bean beetle 7 



(a) Responses of larvae and adults to daylight 7 



(b) Description of dark-room and apparatus 8 



(c) Responses of adult beetles and their larvae in dark-room. ... 11 

 II. Chemotaxis 15 



1. Review of literature 15 



(a) Baits for wireworms and tenebrionids. . .' 15 



(b) Baits for strawberry-root weevils 17 



(c) Baits for the Japanese beetle 18 



(d) Baits for other beetles 24 



(e) Repellents used against beetles 26 



2. Original work on Mexican bean beetle 30 



(a) Search for attractants and repellents, using an olfactometer. 30 



(b) Search for attractants and repellents, using feeding method. 31 



(c) Search for attractants and repellents, using an improved 



feeding method 32 



(i) Beetles can distinguish differences between water and 



salty liquids 34 



(2) Beetles can distinguish differences between water and 



.sour liquids 36 



(3) Beetles can distinguish differences between water and 



bitter liquids 36 



(4) Beetles can distinguish differences between water and 



sweet liquids 37 



(5) Bean foliage sprayed with sweetened arsenicals is more 



attractive than unsprayed foliage 39 



(6) Bean foliage sprayed with arsenicals is repellent 39 



(7) Bean foliage sprayed with sweetened magnesium arse- 



nate is more attractive than foliage sprayed with non- 

 sweetened magnesium arsenate 40 



Smithsonian Miscellaneous Collections, Vol. 82, No. 18 



