62 BRITISH APHIDES. 



This handsome and distinctly marked insect occa- 

 sionally is plentiful on the bird-cherry, Prunus padus. 

 The apterous female occurs in April, but the winged 

 fly is by far the most plentiful form in June. 



Ajjhis ])adi was one of the species chosen by 

 Leuckart to illutrate that portion of his important dis- 

 coveries in 1858 which treated on the generation of 

 Aphides.* He says that the males are wingless, but 

 probably they occur in two forms. 



We are, however, at present ignorant of the different 

 functions performed by such variously formed males in 

 the economy of other species of Aphis. 



Kaltenbach makes the following remarks upon the 

 hybernation of this species ; he says t " Already in 

 September I found winged females and males in 

 great abundance, and likewise a countless number of 

 smaller wingless forms, which most probably would 

 hybernate, since the leaves already had begun to 

 change colour, and some had fallen. The following 

 Spring I put my supposition about hybernation to 

 proof. At the end of March, before the appearance of 

 young leaves, I visited the bush on which, during the 

 previous Autumn, I had noticed the winged females 

 and the males, together with thousands of the young ; 

 to my astonishment, I found that the herd of young 

 Af)hides were in the larval state, and almost grown 

 to their full size. I could find no mother of the colony 

 (Altmiitter) though I searched through the whole 

 herd." 



As the existence of a winged oviparous female has 

 not been proved amongst Aphides, it is probable that 

 some oviparous female was overlooked amongst the 

 apterous forms of the previous Autumn. The occur- 

 rence of the males otherwise would appear to be pre- 

 mature or aimless. If there had been oviposition at 

 that time or subsequently, all cause of surprise at so 

 early a Spring brood would seem to vanish. 



* Leuckart, ' Zur Kenntniss des Generationswechsels.' 

 t ' Kalt. Mon.,' p. 76. 



