FAMILY LIFE 205 



exercised by the female for one special male among a number 

 of others. 



In many male butterflies of the Danaine group there are 

 noticeable dull patches on the wings (either the fore or the 

 hind pair) known as '' brands " ; these are clothed with 

 scales, smaller than those clothing the general wing-area, 

 and overlying little circular or ovoid *' scent-cups " each 

 covered by a cuticular lid with a minute central pore ; beneath 

 each of these is a multinucleate gland which secretes the 

 odorous substance peculiar to the insect (Fig. 56, c, d). At 

 the hinder end of the abdomen, in connection with the genital 

 armature are paired '' brushes " formed of elongate scales 

 usually white or pale in colour. Each brush is carried in an 

 extensible membranous bag ; when this is everted by fluid 

 pressure, the brushes appear as a conspicuous tuft at the 

 male butterfly's tail-end. These remarkable structures on 

 wings and abdomen have been well described by H. H. 

 Freiling (1909) and by H. Eltringham (191 3). The " brush- 

 bag " in Amatiris niaviuSy described by Eltringham, con- 

 tains special groups of cells " which produce numerous 

 delicate chitinous filaments, these having the property of 

 breaking up transversely into innumerable tiny particles, 

 thus forming a kind of dust " (Fig. 56, e,f). The butterfly, 

 provided with this apparatus, brings the abdominal brushes 

 into contact with the scent-brand on the wings, and then 

 by everting them, scatters the perfume around, the '' dust " 

 apparently helping to diffuse the scent. The details of 

 these structures vary in diflFerent members of the family. 

 '* Neither wing-glands nor dust-producing devices are 

 invariably present ; the brush itself and not the wing may 

 produce the scent material . . . whilst the dust may be 

 produced by the wing and not by the brush, and in the pupal 

 instead of in the imaginal state." The scent emitted by 

 these organs may be certainly regarded as an attraction to 

 the opposite sex, but according to an observation made by 

 Hale Carpenter (1920) its effect is not always immediately 

 successful. A male Amauris in Uganda was *' flying about 

 after a female, which presently alighted on a dead flower- 



