CURRANT APHIS. 59 



spicuous " ; in the case of Myziis they are very observable in 

 the male Aphis.* 



The wingless viviparous females are in both species oval, 

 shining yellow or green, with darker green mottlings; cor- 

 nicles, or honey-tubes, paler green ; legs also paler green, 

 yellow, or greenish. R. rihis is a little larger than the other 

 species, being a tenth of an inch in length. 



The ground colour of the winged viviparous female is also, 

 in both cases, yellow or greenish yellow, but there is some 

 difference in the markings of the species. In R. rihis the 

 head, fore body, horns, and feet are black ; and the abdomen 

 has some dark green patches on the back, and some spots on 

 the sides ; honey-tubes yellow, and legs ochreous. In M. 

 rihis the head is pale olive; there are some olive and also 

 some brown markings on the fore body, and several narrow 

 irregular bands on the abdomen, with four or five spots on 

 each edge ; honey-tubes green or olive ; legs green, with 

 olive feet. 



To ordinary observation these little " Green Flies " are so 

 like one another that it is hard to distinguish them apart ; 

 but with a magnifying-glass the markings on the abdomen 

 and the colour of the head are distinguishable. In the pupal 

 condition R. rihis is green ; Myziis rihis green or shining 

 yellow, with two spots on the head. 



The eggs are black, and laid on the shoots of the year. 



The life-history of these aphides (which is similar to that 

 of the others which belong to the division of the AjMdince) 

 may be given generally as follows. The wingless females, 

 which are produced very soon after the males in autumn, lay 

 eggs ; sometimes singly, sometimes in clusters. From these 

 eggs, in the following spring (or possibly before), young 

 aphides hatch, which are all females ; they go quickly through 

 their changes up to the perfect state, and then they produce 

 living young, which also are all females. These successive 

 generations of living young, still all females, some of which 

 are winged, some wingless, go on until, in autumn, the last 

 generation occurs, which is of males as well as females ; and 

 the females of this, as we said before, instead of producing 

 living young produce eggs, which start the next year's 

 attack. 



The Apple and the Cherry Aphis, previously mentioned, 

 and also the Plum Aphis {Aphis prmii), are similar in their 

 life-history to the above, and where kerosine emulsion could 

 be brought to bear on the eggs during wdnter it appears 

 probable that it would act beneficially in preventing their 



* For details, see 'British Aphides,' G. B. Buckton, F.K.S., vol. i. p. 180 

 {Myzus rihis) ; vol. ii. p. 9 {Rhopalosiplmm rihis). 



