1 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 68 



PAGE 



6. Glands at femoro-tibial articulations of beetles and ants as 



scent-producing organs 48 



7. Tufts of hair on tibiae of male moths as scent-producing 



organs 51 



8. Pair of lateral tufts of hair at anterior end of abdomen of 



male moths as scent-producing organs 53 



9. Various structures at ventro-posterior end of abdomen 



of certain Lepidoptera as scent-producing 



organs 54 



(a) Invaginated sacs, tufts of hair and scent groove of 



j certain moths 54 



(b) Styled knobs and invaginated sacs of certain butter- 



flies 56 



10. Anal glands as scent-producing organs 57 



(a) Anal glands of cockroaches 57 



(b) Anal glands of beetles 57 



(c) Anal glands of ants 6z 



11. Invaginated sacs and pouches at dorso-posterior end of 



abdomen as scent-producing organs 63 



(a) Invaginated sacs and pouches of certain Orthoptera 63 



(b) Invaginated pouch of honey-bee 65 



C. Summary of scent-producing organs of insects 65 



Bibliography 69 



INTRODUCTION 



It has always been a matter of conjecture as to how the various 

 lower animals recognize each other, and by what means the sexes of 

 any species distinguish one another. At first thought it might be 

 claimed that sight is the chief means by which any animal having eyes 

 can recognize other animals, but after a second thought we recall that 

 the eyes in the lower animals are not as highly developed as they are 

 in the higher animals ; and we know that many of the lower animals 

 live in dark places and that some of them are partially or totally 

 blind. For example, the eyes of some beetles and spiders inhabiting 

 caves function little or not at all, and despite this fact, these animals 

 seem to distinguish one another as easily as do those with normal 

 eyes living in light places. Relative to blind or partially blind species, 

 touch may be the chief means by which they recognize one another, 

 but during the courtship of cave spiders the writer (1910) observed 

 that the males recognize the females of the same species at short 

 distances and even before the males touch the webs of the females. 

 Touch, therefore, can not be the chief means of recognition for cave 

 spiders and perhaps not for any other animal. Since we know so 



