FAMILY LIFE 203 



another. The method of pairing in Dragon-flies differs 

 most strikingly from that prevalent among insects generally ; 

 the tail processes of the male on the tenth abdominal 

 segment do not clasp, as usual, the hinder region of the 

 female's abdomen, but her neck. The actual copulatory 

 apparatus of a male dragon-fly, exceedingly complex in 

 structure, is situated toward the front end of the abdomen, 

 on the second and third segments. To a central vesicle in 

 this region the sperm-masses are transferred by the male 

 flexing his abdomen ventrally so as to bring the opening of 

 the ejaculatory duct on the ninth abdominal segment into 

 contact with the cavity of the vesicle. Then, in the actual 

 process of pairing, after the male has seized the female 

 by her neck and prothorax, she flexes her abdomen 

 strongly forward so that the spermathecal opening on 

 her eighth abdominal segment is brought against his genital 

 armature. 



Dragon- flies, whose feelers are very small and poorly 

 provided with sense-organs, appear to make little or no use 

 of scent perceptions in their courtship and pairing. Among 

 Lepidoptera, however, the sense of smell is often of great 

 importance as a sex attraction, as has been mentioned in a 

 previous chapter (p. 69), where reference was made to the 

 " assembling " of male moths around a captive female ; 

 moths thus attracted have usually complex feelers with 

 sense-organs abundantly developed. The Swift Moths, 

 whose recognition of mates through vision has just been 

 described, have also the attraction of scent ; the male of 

 Hepialiis humuli emits from the bases of the hind-legs an 

 odour that has been compared to that of almonds, and this 

 probably acts as an auxiliary to his conspicuous white wings 

 for an allurement to the female. In the smaller H. hectus 

 both sexes are alike in their wing-colour ; the male's hind- 

 legs are strongly swollen and the skin glands within these 

 limbs secrete a fragrant fluid whose vapour carries a scent 

 like that of the pine-apple. In these insects, therefore, the 

 male is provided with attractive appearance or perfume or 

 both ; but there is no definite evidence of choice being 



