CHER.MESID^ IN RELATION TO BRITISH FORESTRY. 1 45 



(3) Colonici Generation. — The eggs laid by the Gallicolae on 

 the silver fir hatch in the first days of August. The small red 

 larvae migrate from the needles and anchor themselves on the 

 stem, at the bases of needles, and on buds. Each secretes wool 

 along the margin and crest of the body, and thus passes the 

 winter. These Sistens larvae wake up in March, or earlier if the 

 season be mild. They feed, moult three times, and become adult 

 towards the end of April. Each female lays a large number 

 of reddish-orange eggs under " wool " ( Plate III. Fig. 6). These 

 eggs hatch in about three weeks and .give two kinds of larvae. 



{a) Sistens Type. — These larvae are identical in form with the 

 hibernating larvae. They settle down around their 

 mother on the bark of the shoot or on the buds, 

 secrete " wool '^ as do the hibernating larvae, and thus 

 pass the summer and winter undeveloped. My 

 observations showed that more than half the larvae 

 hatching out were of this type. According to Marchal, 

 some of these larvae develop and become adult during 

 the late summer. They lay eggs from which issue 

 Sistens larvae which hibernate. 



ip) Progredietis Type. — The larvae of this type climb on to the 

 underside of the needles of the silver fir, and feed 

 (Plate III. Fig. 7). These larvae develop into two differ- 

 ent forms. According to Marchal, the difference appears 

 after the second moult. The third moult gives — 



(i.) Nymphs of the Sexupara Generation. 

 (ii.) Wingless larvae. 



These latter larvae moult a fourth time, becoming adult, 

 wingless Progredientes during the second half of June. 

 Each Progrediens lays a number of reddish eggs on 

 the underside of the needles of silver fir, under the 

 protection of copious " wool." These eggs hatch in 

 about two weeks. According to Marchal, they give 

 Sistens larvae which migrate to the branches and 

 buds. Some remain undeveloped until the following 

 spring and some develop. These latter moult three 

 times and become adult. Each lays a number of 

 eggs which, on hatching, give Sistens larvae which 

 pass the winter along with the other first -stage 

 Sistentes. 



VOL. XXXI. PART II. K 



