OLFACTORY ORGANS OF LEPIDOPTERA 41 



never on the tarsi, as observed in the Hymenoptera. A few 

 pores, usually near the distal ends of the tibiae, were seen in 21 

 of these specimens (nos. 1, 2, 3, 5, 7, 8, 11, 12, 19, 22 to 26, 33 

 to 35, 37, 38, 40, 43), and pores were observed in the tibial spines 

 of 12 individuals (nos. 1, 2, 6, 15, 16, 22 to 26, 28, 43). Rela- 

 tive to the isolated pores on the femurs at the position marked 

 a in figure 2 E, one pore was found at this position in 28 speci- 

 mens (1, 2, 3, 6, 10 to 12, 15 to 17, 19, 23, 26, 28, 30 to 41, 43); 

 two pores were found at this position in three specimens (nos. 

 5, 13, 14); four pores at this position in one specimen (no. 42). 



c. Generic, specific and sexual variations. The generic and 

 specific variations are considerable when the total number of 

 pores is considered. The noctuids (Nos. 4 to 9, table 1, p. 

 43) well illustrate the generic variation and the three species 

 of Pontia (nos. 35 to 37) illustrate the specific variation. The 

 total number of pores of the noctuids vary from 852 to 1422, 

 with a difference of 570 pores, and the species of Pontia from 

 632 to 784, with a difference of 152 pores. 



Excluding the females with rudimentary wings, the sexual 

 variation is insignificant. The male each of Bombyx (nos. 13 

 and 14) and of Sanninoidea (nos. 19 and 20), the peach-tree 

 borer, has 13 more pores than has the female of the same species. 



The male of the tussock moth, Hemerocampa leucostigma, was 

 not examined, but the number of pores on the rudimentary wings 

 of the female (no. 10) does not seem to be greatly reduced. The 

 front wings are plainly visible to the unaided eye, but the hind 

 wings are not, and both pairs are nothing less than thick pads 

 in which the veins are not distinct. As in Bombyx, three groups 

 of pores (nos. 1 to 3) lie on the dorsal surface of each front wing 

 (fig. 3 A) and one (no. 4) on the ventral surface; nos. 5 and. 6 

 are present on the dorsal surface of the hind wing (fig. 3 B), 

 but no. 7, usually present on the ventral surface of the hind wing, 

 is absent. The scattered pores on the front wings are twice, 

 and those on the hind wings are three times as large as the ones 

 in the groups; ordinarily the scattered pores are little, if any, 

 larger than those of the groups. 



