MALE ORGANS. 123 



perhaps may be found in the fact that the male is 

 polygamous, and will visit many females. 



The males nevertheless occur in two forms. The 

 winged varieties are large insects, whilst the apterous 

 males are very small, and sometimes so diminutive 

 that they were for a long time overlooked altogether. 



Kyber's opinion of the non-necessity of the male 

 to perpetuate a cycle doubtless was in a measure 

 formed from a belief in its non-existence. The neces- 

 sity of the male at certain periods, however, would 

 seem now to be proved by this dimorphism. The 

 winged insect is fitted for long flights, and by its visi- 

 tation makes a provision against "in and in " breed- 

 ing ; whilst the influence of the minute apterous insect, 

 which is often incapable of nourishing itself, must be 

 very circumscribed. 



The winged males of the higher genera of Aphides 

 are often elegantly marked and of bright colour. They 

 are fully-developed insects, provided with large eyes, 

 compound and otherwise, and also with long, well 

 accoutred antennas, to assist them in their roving 

 expeditions. 



The apterous males also are often brightly coloured ; 

 but in the lower genera, such as Schizoneura, Pem- 

 phigus, and Ohermes, &c, they appear to be little more 

 than animated locomotive sperm-cells. They possess 

 neither eyes nor mouths, they have only rudimentary 

 digestive apparatus, and consequently, after fulfilling 

 their office, they speedily die. 



The external genital organs of the male Aphis have 

 been well described by Balbiani, and his memoir 

 is elaborately illustrated.* If exception can be taken 

 to his illustrations of Aphis, it may be said that they 

 are too diagrammatic. The figures are symmetrical, 

 and they form elegant drawings ; but the conditions 

 are not such as can be seen immediately, and at one 

 view, under the microscope. 



* Balbiani, " Generation des Aphides," ' Ann. des Sc. Nat.,' 1869, 

 15 ser., t. si. 



