290 



INTRODUCTION TO ZOOLOGY 



We find, therefore, on the spruce from October to December, 

 hibernating females of two kinds : 



(1) Those arising from the parthenogenetic eggs of the 

 Chermes abietis which has never left its spruce home ; 



(2) Those arising from the fertilised egg laid on the 



B 



ocfuoJ sij 



FIG. 216. 



A, Larch infested by Chermes ; e, cluster of stalked eggs ; B, cluster of eggs enlarged, 

 showing wax (w) surrounding them ; h.f t hibernating mother ; Us an egg in which 

 the new individual is almost developed ; D, view of I enlarged ; C, hibernating 

 female on larch, much enlarged. 



spruce. These are the fourth generation from that Chermes 

 abietis which migrated from spruce to larch in the August of 

 the previous year, and whose second generation of descendants 

 returned to the spruce in the summer of the second year in 

 the cycle under consideration. 



