ALLURING OR SCENT-GLANDS 



391 



THE ALLUKING OR SCENT-GLANDS 



It is difficult to draw the line between repelling and alluring 

 glands. Attention was first definitely called to the alluring odors 

 of Lepidoptera by Fritz Miiller, who showed that the males of certain 

 butterflies are rendered attractive to the other sex by secreting odor- 

 ous oils of the ether series. He pointed out that the seat of the odor 

 is the androconia (see p. 199), while either repellent or pleasant 

 odors are exhaled from abdominal glands. 



Those of Pieris napi yield a scent like that of citrons, Didonis biblis gives off 

 three different odors from different parts of the body, besides having a distinctly 

 odorous spot on the hind wings. Both sexes have a sac between the fourth and 

 fifth abdominal segments which exhales a very unpleasant (protective) odor, 

 while the males have on the succeeding segment a pair of glands from which 

 proceeds an agreeable odor like that of the heliotrope. Callidryas argante throws 

 off a musky odor. In Prepona laertes the odor is like that of a bat, in Dircenna 

 xantho it is vanilla-like, the androconia being situated on the front edge of the 

 hind wings. In Papilio yrayi the odor is said to be as agreeable and intense as 

 in flowers. Certain sphingids are known to exhale a distinct odor, which Miiller 

 has traced to a tuft of hair-like scales at the base of the abdomen, and which fits 

 into a groove in the first segment, so as to be ordinarily invisible. 



In the noctuid genus, Patula, the costal half of the hind wing is modified to 

 form a large scent-gland, and in consequence the venation has been modified. 

 The still greater distortion of the veins in the allied genus, Argida, was attributed 

 by the author to its once having 

 possessed a similar scent-gland, 

 now become rudimentary by dis- 

 use. (Hampson.) 



Peculiar white or orange-colored, 

 hairy, thread-like processes have 

 been found protruding from nar- 

 row openings near the tip of the 

 abdomen of Arctian moths (Fig. 

 367), which throw off, according to 

 J. B. Smith, "an intense odor, 

 somewhat like the smell of laud- 

 anum." We have perceived the 

 same unpleasant odor emanating 

 from the males of Spilosoma vir- 

 ginica and Arctia virgo, as well 

 as Leucarctia acrcea. 



We are informed by C. Dury ^ 36T ._ 8cent . tuft9 . ^ of Leucaretia atiraia; 

 that similar but longer hairy ap- 2, of PyrrarcUa Isabella. After Smith, 

 pendages are thrust out by the 



male of Haploa clymene. Many glaucopid moths protrude similar glandular 

 processes. Thus Mtiller tells us that on seizing a glaucopid female by the 

 wings, nearly the whole body became enveloped in a large cloud of snow-white 

 wool which came out of a sort of pouch on the ventral side of the abdomen. 



The male of a glaucopid was seen to dart out a pair of long hollow hairy re- 

 tractile filaments which in some species exceed the whole body in length. The 



