142 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



(3) Co/onici Ge/ierafiou. — The resulting larvae moult four 

 times and become wingless adults. Egg-laying is spread over 

 a considerable time. The larvae hatching from these eggs 

 moult two or three times, then hibernate. In this species, 

 therefore, the hibernating larvae on the intermediate host do not 

 hatch from eggs laid by the Gallicolae as in other Chermesidae, 

 but from eggs laid by descendants of the Gallicolae. 



Development in spring and summer is as in "(^) The 

 Indigenous Race," but more Sexuparas than Colonici alatce are 

 produced. 



(4) Sexupara Generation. — Development is as in " {A) The 

 Indigenous Race." The winged Sexuparae migrate to the needles 

 of Picea orientalis, very rarely to P. excelsa. This migration 

 takes place in the second half of June. Each female lays 

 about ten yellow eggs under the protection of " wool." 



(5) Sexuales. — Larvae of both males and females hatch out 

 from these eggs. After four moults they become adult, and 

 each female lays a single yellow fertilised egg on the twig of 

 Picea orientalis. 



The following is a diagram illustrating the life-history of 

 Pineus pini (Oriental race), according to Marchal : — 



Fig. 2. — Diagram of the Life-Cycle oi Pineus pini (Oriental race), 

 according to Marchal. 



Pineus strobi (Htg.), Borner. 



In Europe this species is only found on Weymouth pine 

 {Pinus strobus). Marchal observed that the Sexuparae settled 

 on the needles of black spruce {Picea 7iigra) and laid eggs. 

 Only females issued from these eggs, thus the cycle was similar 

 to that of Pineus pini (Indigenous race). As both Picea nigra 

 and Pinus strobus are East American trees, it is possible that 



