a Note on the early stages of its development. 



13 



Primary Host, 

 Picea 



Intermediate Host, 

 Larix (or Pinus, or Abies) 



T Fiinrffltrires \hibcmate— cause galls- 



1st 

 year 



II. 



Alatae 



Non 

 migrantes 



Klarvae inhabit gall — 

 (adults winged — all ? 



Migrantes 

 I 



I. Fundatrices (as before) 



2nd 

 year 



( hibernate — cause 

 III. Colonici \ no gall — wing- 

 [less — all ¥ 



larvae live on the 

 needles — cause no 

 gall — all ¥ 

 IV. Sexuparae Exsules 



adults winged adults ivingless 



Iivingless — 

 cause no 

 gall — cf <& ¥ 



II. 



Alatae (as before) 

 Non 

 migrantes Migrantes 



Exsules 



-to Larix 

 as before 



I 

 I. Fundatrices I. Fundatrices 



The gall arises in the following manner : — 



In the autumn a Chermes larva drives its long proboscis either 

 into the stem of the Spruce just below a bud or into the bud itself, 

 and thus securely anchored, passes into a hibernating condition. 

 The insects at this stage are very minute, their total length barely 

 exceeding 0'5 mm., but they are provided with an extremely long 

 proboscis which is about three times as long as the whole body. 

 This proboscis is driven right through the cortex and the apex 

 lies in the neighbourhood of the cambium. Once the insect has 

 established itself in this position she never again quits the spot, 

 but here remains until her death in the following June. 



Before passing on to the development of the gall it will be well to 

 recall briefly the structure of the normal winter bud of the Spruce. 



