46 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 68 



canal, which opens freely at the tip. Another type possesses many 

 longitudinal canals whose external openings lie at the tip of the fringe 

 that crowns the scale, or the surface of the scale is perforated by 

 fine holes like a sieve. The odor that comes from a wing may be 

 likened to that from a lemon, or a balm-tree blossom. 



Aurivillius (i88oa-b) calls these scales a secondary sexual char- 

 acter and based on their shape he has divided them into seven diflferent 

 types. This author found them in no species, representing seven 

 families. 



Von Dalla Torre (1885) says that the females of many lepidopter- 

 ous insects give out odors perceptible to the males, and thereby 

 induce copulation. It seems proven that by extending the ovipositor 

 the female can cause the dissemination of the odor which attracts 

 the male. In all male specimens of Callidryas argante examined, a 

 musky odor was emitted from the scales when exposed on the wings. 

 In Prepona larrtcs the odor is like that from a bat, and in Dircenna 

 xantho it resembles that from vanilla. That we are unable to per- 

 ceive a distinct odor from these scales in every species does not argue 

 against the idea that the scales emit an odor, because the sense of 

 smell is much more highly developed in the Lepidoptera than in man. 



Haase (1886b, 1887, i888a-b) made a special study of the scent 

 .scales of many families belonging to the Indo-Australian butterflies. 

 He found them usually grouped in brightly colored felt patches and 

 considers them as a secondary sexual character. The odor emitted 

 by several species is similar to that from vanilla. The scales lie 

 so protected while at rest that an unnecessarily rapid evaporation 

 is prevented. 



Thomas (1893) says : " When scattered irregularly over the wing 

 they are always underneath the large scales and therefore well pro- 

 tected." He was the first to prove by making sections through the 

 wing that a secreting cell lies at the base of each scale. There is 

 often a canal extending from the base to the tip of the scale where 

 the secretion may find a direct outlet, or it may disappear in the 

 spongy mass found at the end of these androconia. 



Kellogg (1894) caught a male of Pieris rapcc, and after rubbing 

 the upper surface of the front wing with the finger, he then smelled 

 his finger and at once perceived a distinctly pleasing aromatic odor. 

 This test therefore proves that the scales emit an odor. 



Spuler (1895) shows that the dorsal surface of a scale is usually 

 covered with many longitudinally parallel ridges while the ventral 

 surface is smooth. There are also sometimes smaller transversely 



