Insects, etc.. Injurious to Currants. 223 



THE WHITE WOOLLY CURRANT SCALE. 



{Pulvinaria vitis var. ribesiw. Signoret.) 



This species during the greater part of its existence is one of the 

 most marlved of the Coccidas we find in G-reat Britain, and cannot 

 -well be confounded with any other outdoor species. But durin'i- its 

 young scale stages it may be mistaken for the Brown Currant Scale 

 ■{Lccanium iicrsicm var. sarothamni). 



The White Woolly Scale can readily be told during the summer 

 by the presence of a large quantity of white wool, which first appears 

 ^s a cushion beneath the insect, and which gradually pushes it away 

 from the bark. The white cushions spread out and the fibres become 

 loose and get blown about by every breath of air, threads of extreme 

 fineness being spread from twig to twig and bough to bough like 

 spiders' webbing. Bushes when badly attacked look just as if spiders 

 had spun their webs over them and the bushes had been dusted with 

 lime or white-wash. Figure 171, reproduced from a photograph, shows 

 •the appearance of an infested branch. The specimen came from some 

 bushes in Huntingdonshire which were completely covered, as shown 

 in the figure. It is a species readily distributed by the wind and by 

 birds. 



The dead dried insect is dull greyish-brown, of a roundish oval 

 form, about | to J- inch long, and like the Brown Currant Scale, with 

 SL distinct notch at the posterior end of the body. The edges become 

 <;urled up and the surface is very convex, and some trace of a keel is 

 seen running down the back, and transverse lines running down from it 

 to the sides. The adult female at the period of parturition is dusky 

 jellow, almost covered with dark brown reticulations which may form 

 indefinite transverse lines ; after parturition, dark brown or chocolate- 

 brown to black. At the period of fecundation the female becomes 

 slightly elongate and widened posteriorly ; colour dusky yellow, with 

 a median bright line and distinct dark brown reticulations. In the 

 winter the insect fits close to the bark, but by degrees a thick, rather 

 close cushion of wool appears, and gradually lifts one end of the insect 

 up ; as this grows it becomes irregular and loose threads get blown 

 from twic to twig and hang about in the air. In this mass of m'ooI 

 the female lays her eggs. The eggs are small, pale, dust-like bodies, 

 which I have found as early as July (1). ISTewstead finds that the 

 larvfe hatch early in June. Some ova I kept for a week ; they then 

 "ave rise to little, orange, six-legged larvae which moved about actively 

 on the wool and over the twigs ; the deep cleft in the caudal 



fa 



