CHERMESID.B IN RELATION TO BRITISH FORESTRY. 1 35 



and to become pale and swollen. Later, numerous red papillae 

 appear on the swollen parts. 



(2) Gallicola Generation. — The larvae hatching from the eggs 

 laid by the Fundatrices crowd amongst the deformed needles 

 of the spruce bud. As a result of the feeding of these larvae, 

 the swollen needles close together, forming a compact gall con- 

 sisting of chambers in which the larvce feed (Plate II. Fig. i). 

 The third moult gives a nymph stage, characterised by rudimentary 

 wings. When this stage is full-fed, the gall turns brown and opens. 

 The nymphs climb out, and the fourth moult gives the yellow 

 adult, Gallicolae non-migrantes. These settle on the spruce on 

 which they were born, or on adjacent spruce, and lay 25-40 

 bright yellow eggs. No " wool " is secreted by these Gallicolae. 

 The eggs hatch in two to three weeks. Development within 

 the gall is variable, and the galls of this species open from the 

 second half of July until mid-September. 



Chermes viridis (Ratz.). 



The life-cycle of this species consists of five generations — 

 Fundatrix to Sexuales. It is passed on spruce and larch, and 

 takes two years to complete. 



(i) Funddirix Generation. — The Fundatrix hatches from a 

 fertilised egg during the latter half of August. In spring, when 

 adult, it lays 40-50 green eggs under some "wool." It in all 

 other ways resembles Ch. abietis, Kalt. 



{2) Gallicola Generation. — The development of the larvae of 

 the Gallicolae and of the gall is as in Ch. abietis, Kalt. The 

 galls open in the second half of July, or the first half of August. 

 The reddish-yellow Gallicolae migrantes migrate from the spruce 

 to the needles of larch. There they lay 25-30 dark green eggs. 

 No " wool " is secreted by the adult Gallicolae. 



(3) Colonici Generation. — These eggs hatch in about three 

 weeks. The dark green larvae migrate from the needles to the 

 bark of the trunk or of the branches of larch. They settle in 

 a crevice and secrete short curly " wool," which gives them a 

 grey appearance. Parts exposed to intense light, such as the 

 tops of trees and the upper sides of branches, are avoided. In 

 March these larvae wake up and feed. They moult three times 

 and become adult towards the end of April. Each green 

 female lays 20-30 green eggs under the protection of copious 



