45o 



The Genus Chermes. 



[SEPT., 



In the winter condition examination of the upper surface of the 

 abdomen of the larva, and of the mesothorax and metathorax, reveals 

 six longitudinal rows of chitinous glandular plates ; these plates on 

 the prothorax and the head have coalesced into larger structures. The 

 plates bear the pores from which the wax or wool exudes. The follow- 

 ing is a comparison of the hibernating foundresses of C. viridis and 

 abietis with those of C. strobilobius and lapponicus. 



C. viridis. C. strobilobius. 



At the head end .2 large plates, At the head end are 2 large, four- 



which have at their corners groups of sided plates, which have at eadh corner 



4 to 5 pores surrounding a fine hair. a single large wax pore. 



On the prothorax are 2 large, On the prothorax are 2 large, central 



squarish central plates with groups of square plates with a large pore at each 



pores 3 to 5 in number, and 2 oval corner, and also 2 oval side plates, 

 side plates with pore groups at the 

 front and hind ends. 



On the mesothorax and metathorax On the mesothorax and the meta- 



are 4 small, 4-cornered, 4-pored plates, thorax and on the abdominal segments 



and 2 oval 8-pored plates. are 6 small plates each of which bears 



The abdominal rings have each 6 a single prominent pore (under a high 



small plates ; these plates on the front magnification each large pore is found 



rings are 4-pored, and on the hind ones to be surrounded by a series of tiny 



2-3-pored. pores). 



Of the remaining species of Chermes that may be present in Britain 

 the knowledge regarding the insects and their life history is very 

 incomplete. We have representatives at least of species whose inter- 

 mediate host is Pinus or Abies. 



Chermes whose Intermediate Host is Pinus. 



Of such Cholodkovsky describes two, viz., Chermes orientalis 

 Dreyfus, and Chermes pint Koch. 



The primary host of orientalis is Picea orientalis, the Oriental 

 Spruce, and rarely the common spruce, Picea excelsa; the intermedi- 

 ate host is a Pinus. 



The primary host of Chermes pini has not yet been absolutely 

 proved ; the intermediate hosts are Pinus sylvestris and Pinus Strobus, 

 the Weymouth pine. It has been suggested that further research may 

 show C. orientalis and C. pini to be one and the same, with Spruce as 

 the primary host tree, and Pinus sylvestris and Pinus Strobus the 

 intermediate hosts. In its life history there would be five generations 

 with an Exile Series in Generation 4, the Exile Series containing in 

 this case, not only wingless adults, but also winged non-migrating 

 adults. 



The galls on Picea in the case of C. orientalis are elongated and 

 cylindrical, the foundress larvae hibernating on the stem below the 

 bud, the bud-gall being, as a consequence, not so marked. Burdon 

 has found the galls on Picea orientalis. Of the above group * 

 of Chermes a stage on the intermediate host Scots Pine has 



* In the literature apart from the nomenclature of Cholodkovsky, we have for 

 pine-infesting forms the names C. strobi Hartig, and C. corticalis Kalt. 



