OLFACTORY ORGANS OF LEPIDOPTERA 35 



THE OLFACTORY PORES 



Before making a study of the anatomy of the organs, called 

 the olfactory pores by the writer ('14 a), the distribution and 

 number of them were first investigated. 



Dis-position 



In making a comparative study of the disposition of the 

 olfactory pores in Lepidoptera, 40 species, belonging to 36 genera 

 and representing 19 families, were used. In most cases only- 

 one specimen of each species was employed, and whenever a 

 portion of an appendage or an entire appendage was missing or 

 was badly mutilated in being prepared for study, the supposed 

 number of pores on this portion or entire appendage was regarded 

 the same as the number found on the corresponding portion or 

 entire appendage on the opposite side of the body. Since the 

 pores on only one specimen for each species were counted, the 

 total number of pores recorded can not be a fair average. Be- 

 sides this error, there is also another small probable error for 

 each species, because a few of the pores were probably over- 

 looked, and often, as on the tibiae, it was impossible to distin- 

 guish the olfactory pores from hair sockets. Only the legs, 

 wings and mouth parts were examined, although in two or three 

 instances the chitinous parts of the reproductive organs were 

 also examined, but no olfactory pores were seen on them. The 

 mouth parts of more than one-half the specimens were either 

 missing or were so mutilated that the pores on them could not 

 be counted; nevertheless, regardless of all the errors, the total 

 numbers of pores recorded are probably not far from being accu- 

 rate, but they are perhaps always shghtly less than the numbers 

 actually present. The sex of the species, except in tour cases, 

 was not determined. 



a. Bombyx mori 9 . Since the silkworm moth, Bombyx mori, 

 is conveniently studied and , as its olfactory pores are typical foi 

 most of the moths examined, the disposition of them will be 

 described in detail, and then the variations found in the other 

 species will be given. 



