NO. 2 RECOGNITION AMONG INSECTS — McINDOO S3 



cavity of the scale which is filled with a granular matrix and then it 

 infiltrates to the exterior through pores that are closed with very thin 

 chitin. It may also be assumed that some of the secretion passes out 

 of the pore around the base of the scale and then runs down the sur- 

 face of the scale between the ridges. He thinks, therefore, that the 

 scales are a means of spreading the liquid over a large area for quick 

 evaporation. 



Illig (1902) describes the scent-producing organs in the males 

 of Syrichthus malvce as fan-shaped tufts of long and slender hairs 

 which lie on the proximal ends of the tibias of the hind legs. Muscle 

 fibers are attached to the bases of these hairs to move them and a 

 large gland cell lies at the base of each hair. Since- the hairs do not 

 open at their tips, the secretion evidently comes to the exterior 

 through the pores around the bases of the hairs ; but on the surface of 

 the spatula-shaped hairs of Hepialus hecta he thinks that he saw fine 

 pores through which the secretion probably issues. In Pechipogon 

 barbalis the scent-producing organ consists of three tufts of hair 

 on the front legs. The largest tuft lies at the distal end of the femur ; 

 one of the smaller ones midway between the ends of the tibia, and the 

 other small tuft at the distal end of the tibia. The morphology of 

 these three tufts and of their unicellular glands is very similar to 

 that of Syrichthus fnalvcF. 



8. PAIR OF LATERAL TUFTS OF HAIR AT ANTERIOR END OF ABDOMEN OF 

 MALE MOTHS AS SCENT-PRODUCING ORGANS 



Stefanelli (1870) says that only the males of Sphinx convolvuli 

 emit an odor. The odor is strong but agreeable, resembling amber 

 or musk. It comes from two lateral grooves on the first abdominal 

 segment. The openings of the grooves are guarded by bunches of 

 yellowish hair. 



Tozzetti (1870) describes the scent-producing organ of the same 

 species as follows : It consists of a pair of deep grooves, each one 

 of which lies in the pleura of the first and second abdominal segments 

 on either side. The groove is filled with long, slender, scalelike 

 hairs. Each hair has a peculiar ringlike base whose lowermost por- 

 tion extends into a long process which is inserted into a chitinous 

 socket. Beneath the socket lies a unicellular gland containing a 

 large nucleus. 



Swinton (1877) saw this organ in Acidalia remutata and during 

 copulation he observed that it expands. He also noticed it in 

 Acherontia satanas; here it may be expanded into a stellate shape 

 and a pungent odor of jessamine is emitted. 



