550 PROCEEDINGS OF THE ACADEMY OF [Aug., 



glands, each of which communicates with a spatula-shaped hair 

 (Bertkau, 1882). In the male moth Phassus schamyl the hairs are 

 scalelike with the distal end of each scale divided into two or three 

 lobes (Deegener, 1905). The same kind of organ is found in the 

 male moths Syrichthus malvce and PecMpogon barbalis (lUig, 1902). 

 In the latter species, instead of there being a tuft of hairs on each 

 hind tibia, each front tibia bears three tufts. In the male moth 

 Sphinx convolvuli a pair of lateral tufts of scaleUke hairs is found at 

 the proximal end of the abdomen (Tozzetti, 1870). In the female 

 moths Taumatopoca pinivora and Stilpnotia saiicis the scent-producing 

 organ is a large paired tuft of hairs on both sides and above the anus 

 (Freiling, 1909). In many male butterflies, the scent scales on the 

 wings serve as scent-produCing organs (Mtiller, 1877). Each scale 

 is connected with a unicellular gland (Thomas, 1893; Illig, 1902). 

 In the second type of scent-producing organ, the secretion from the 

 gland cells passes into the hairs and scales and then spreads over 

 their surfaces, whereby the odor from the secretion is more effectively 

 disseminated. 



In regard to storing the odor in an "evaginable" sac, the third 

 type is a little farther advanced than the second type. In the male 

 butterflies Danais and Euplcea the scent-producing organ consists 

 of two large chitinous invaginated sacs, lined with scalelike hairs. 

 One of these sacs lies on either side of the abdomen and opens between 

 the seventh and eighth sterna (Illig, 1902). In the female butterfly 

 Gonopteryx rhamni this organ is a single invaginated sac, but in the 

 female of Euplosa it consists of a circle of scalelike hairs around the 

 anus and of a pair of invaginated sacs, lined with hairs as usual 

 (FreiUng, 1909). Each hair is connected with a unicellular gland. 

 The sacs are evaginated by blood pressure and retracted by muscles. 

 It is thus seen that the odorous substance may be more or less 

 retained in the invaginated sacs, but when the sacs are evaginated, 

 like the fingers of, a glove, all the odor escapes. 



In regard to storing the secretion, the fourth type is more highly 

 organized than any one of the preceding types of scent-producing 

 organs. In the roach Periplaneta orienlalis this organ consists of a 

 pair of shallow pouches in the articular membrane between the 

 fifth and sixth abdominal terga. The pouches are covered by the 

 fifth tergum, but open to the exterior by a pair of slit-shaped open- 

 ings. They are lined with hairs, each of which connects with a 

 unicellular gland (Minchin, 1888). In the sexually matured male 

 roach Phyllodromia germanica there are two double pouches, one 



