APTEROUS MALES. 47 



were no true males amongst Aphides. It is difficult 

 to explain why, notwithstanding their completeness, 

 De Geer's observations seem in effect to have been at 

 one time almost ignored or else forgotten. His words 

 are of interest. Their substance is as follows : 



Towards the end of autumn in August, 1746, I 

 found this Aphis of the apple-tree sparsely scattered. I 

 saw the male in conjunction with the female, and I 

 also witnessed the process of oviposition by the latter. 



Again he says, at another time, amongst these 

 Aphides I found two individuals, one of which sat on 

 the back of the other. I watched under a lens the 

 actual process, and saw a connection of their hinder 

 parts. To convince myself of the accuracy of my 

 observation, I touched the uppermost insect, which I 

 considered to be the male. Immediately it put itself 

 into an agitated state in order to disengage itself. 

 " Hier sah ich deutlich, das sie einen kleinen hautigen, 

 durchsichtigen Theil aus dem Leibe des Weibchens zog, 

 der auch noch eine Zeitlang aus ihr herausging, hernach 

 aber allmalig wieder zuruchgezogen werde." 



He then says that he subsequently saw other males 

 in coit'ii, and unexpectedly, that they were apterous, 

 like those of the fir-feeding Aphides which he de- 

 scribes. The chief difference between the males and 

 the complete females of this species, he states, is the 

 more slender form and ringed abdomen of the former, 

 and that a row of dark spots occurs down the sides of 

 the back. 



After noticing the colour of the eggs and the spots 

 chosen by the mother for depositing her ova, he 

 remarks that after the coitus and the completion of 

 the egg-laying they both died. 



Kaltenbach queries De Geer's remark that the male 

 is always apterous. Since Kaltenbach's time Mr. 

 Walker has described a winged male of Aphis mali, 

 and he seems to have seen it pair in October. This 

 alate character seems to militate against De Geer's 

 previous discoveries. But Leuckhart dissected the 



