ORDER LEPIDOPTERA. 



149 



are in parts clothed with peculiar hairs, called androconia 

 (Fig. 178). Fritz Miiller has shown that the males of 

 certain butterflies are rendered attractive to the other sex 

 by secreting odorous oils of the ether series. 



Certain hair-like scales on some butterflies give off an 

 odor, in Pier is napi like that of citrons, while P. rapes 

 is slightly odorous; and Miiller has observed in the male 

 of Didonis biblis three different odors in different parts 

 of the body. The females of Callidryas have in the end 

 of the body highly odorous glands, while the males give 

 off a musk-like odor from the same parts. 



FIG. 177. Scent-tufts of moths. 1, Leucarctia 

 acrcea; 2, Pyrrharctia Isabella. After Smith. 



FIG. 178. a. scent-scales or 

 androconia; 6, ordinary 

 scale of Lycsena butter- 

 fly. Highly magnified. 

 After Scudder. 



Peculiar white or orange-colored, hairy, thread-like pro- 

 cesses have been found protruding from narrow openings 

 near the end of the hind body of certain moths (Fig. 177), 

 which give out, according to Mr. J. B. Smith, "an intense 

 odor, somewhat like the smell of laudanum." 



While there is great uniformity in the shape of the body 

 of butterflies and moths, their habits are, within narrow 

 limits, quite diverse. Some fly by day, others at dusk, 

 others by night. The great number of species, of which 

 there are estimated to be 25,000, is undoubtedly due to the 

 variety in the food-plants on which the caterpillars feed. 

 Nearly if not every species of plant affords room and board 



