Currant Aphides. 



309 



The insects spread chiefly by means of winged generations, 

 which appear every now and then, flying from bush to bush, 

 and there setting up fresh areas of disease. These winged 

 generations may occur as early as the middle of May, but 

 usually not until June. 



These two insects seem to have been treated as one ; Miss 

 Ormerod merely calls them Aphis ribis, but the two are 

 perfectly distinct. Myzus ribis occurs abundantly on the 

 Continent : Kaltenbach speaks of it as destructive in Ger- 

 many, and Taschenberg also refers to it as forming lumps 

 and curling up the leaves. 



It appears to have been imported into America, for 

 Saunders mentions it as an imported insect. Lintner also 

 says it is destructive in the States. 



Life-history. 



The appearance and habits of the two commonest currant 

 Aphides are different, but their life-history is very similar. 



(I.) Rhopalosiphum ribis, Linn. — The wingless viviparous 

 female, or " Mother Queen," is shiny green, mottled with 

 darker green ; legs, cornicles, and antennae pale green ; eyes, 

 red. In form it is oval and convex, and larger than the 

 species named below (II.) ; the body being one -tenth of an inch 

 long. The wingless females are found under the leaves and 

 cause the red, reddish-brown, orange, and yellow blisters. 

 They appear first of all in April, and occur continuously 

 until July and even August. Every noAv and then the lice 

 to which they give rise turn into pupae ; rudiments of wings 

 appearing as wing-buds. 



The pupa is green, and does not differ much from the 

 wingless female or larva. The winged viviparous female, 

 which arises from the pupa, is yellowish-green with black 

 head, antennae, joints to the legs, black thorax with a yellow 

 band in front ; the abdomen is bright yellowish green, with 

 dark spots and patches on the dorsum and sides; yellow 

 honey-mbes, swollen towards the apex ; ochreous legs with 

 dark joints. These winged females fly from bush to bush. 

 .In the autumn or late summer males and ovigerous females 



