56 ■ SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 68 



have a powerfully attractive force of some kind which causes the 

 males to congregate around them, although he was never able to 

 detect any odor coming from these sacs. With a piece of filter 

 paper he drew some of the secretion from the outer surface of the 

 evaginated sacs and then placed the paper in front of a freshly 

 emerged male. The same reactions were obtained as when a male 

 had been given access to a female in a box ; at once the male threw 

 himself upon the paper as if it were a female. While experimenting 

 with silkworm moths, Kellogg (1907) obtained similar results and 

 he says : " If the cut-out scent-glands are put by the side of and 

 but a little apart from the female from which they are taken, the 

 males always neglect the nearby live female and go directly to the 

 scent-glands," and try to copulate with them. 



(b) STYLED KNOBS AND INVAGINATED' SACS OF CERTAIN BUTTERFLIES 



Mitller (1877a) regards a pair of small styled knobs, found only 

 in the females of maracuja butterflies, as a scent-producing organ. 

 In shape they are similar to the halteres of flies and lie on the 

 posterior edge of the abdominal penultimate segment. The knobbed 

 portion of the organ, which he thinks secretes a fluid, is covered with 

 scales. 



Illig (1902) says that the scent-producing organ in the male of 

 Danais pexippus and Euploca consists of two large chitinous, invagi- 

 nated sacs, one of which lies on either side of the abdomen and opens 

 to the exterior by a wide aperture between the seventh and eighth 

 sterna. Scalelike hairs are attached to only the anterior portion of 

 these sacs and a gland cell is found at the base of each hair. The 

 secretion probably finds its way to the exterior through the socket 

 around the base of the hair. This organ is evaginated by blood pres- 

 sure and retracted by muscles. 



Freiling (1909) says that in the female of Gonopteryx rhamni 

 this organ is an invaginated sac lined with scalelike hairs, opening 

 between the seventh and eighth sterna. In the female of Euplcea 

 asela the organ consists of a circle of scalelike hairs on the eighth 

 segment around the anus and of a pair of invaginated sacs lined with 

 hairs. These sacs open to the exterior between the seventh and eighth 

 sterna. In the males of Euploea asela and Danais septenfrionales 

 this organ is a pair of invaginated sacs, one of which lies on either side 

 of the abdomen with its external opening at one side of the anus 

 between the seventh and eighth segments. Most of the scent hairs 

 are attached to the anterior portion of the sac and when the sac is 



