34 N. E. McINDOO • 



In 1857 Hicks discovered pore like organs on the wings of 

 Lepidoptera and called them vesicles. He says: ''In moths they 

 are very apparent, being greatest in the noctuae [Noctuidae] and 

 Bombycidae. There are about 100 vesicles on the upper sur- 

 face of the posterior wing, and half that number beneath, be- 

 sides some few on the nervures [veins]. In the butterfly they 

 are smaller, but arranged in more definite groups, about three in 

 number." In 1860 Hicks discovered them on the legs of Lepi- 

 doptera, and the present writer ('14 a and b, '15 and '16) has 

 made a comprehensive study of these organs in Hymenoptera 

 and Coleoptera, and since he proved experimentally that they 

 receive olfactory stimuli, they were called olfactory pores. On 

 account of other investigations, the writer has not had time to 

 determine the physiology of these organs in Lepidoptera and for 

 this reason the present paper deals with only their morphology. 

 To obtain material for the study of the disposition of the 

 olfactory pores, dried museum specimens were mostly used. In 

 regard to preparing the specimens with caustic potash and to 

 bleaching them with chlorine gas, the reader is referred to the 

 writer's work on Hymenoptera ('14 b, p. 295). 



To obtain material for the study of the internal anatomy of the 

 organs herein discussed, moths emerged a short time from the 

 cocoons and a butterfly were used. The material was fixed in 

 Carnoy's fluid (equal parts of absolute alcohol, chloroform, 

 glacial acetic acid, with corrosive sublimate to excess) and was 

 embedded in celloidin and paraffin. The sections were cut five 

 and ten microns in thickness and were stained with Ehrlich's 

 hematoxylin and eosin. 



All the drawings were made by the writer and all are original 

 except figure 10, which represents the antennal organs of a 

 moth and was copied from Schenk ('02). The drawings were 

 made at the base of the microscope with the aid of a camera 

 lucida. 



The museum specimens were secured through the courtesies 

 of Dr. L. O. Howard and Mr. August Busck, and the writer is 

 also grateful to Mr. Carl Heinrich for verifying the identification 

 of all the Lepidoptera used. 



