40 First Report on Economic Zoology. 



Chermes corticalis, Kalt, on Pine Trees. 



Conifer shoots and bark, sent by a correspondent of tlie Board of 

 Agiicultiire from Holmleigb, Matfield, Paddock Wood, Kent, covered 

 with a plant louse which belonged to the genus Chermes, several of 

 wliicli attack conifers. It is known as Chermes corticalis, Kalt. 



The apterous female is small, oval and yellowish-brown in colour, 

 the abdomen exuding a large quantity of white, flocculent silky matte 

 mixed with white meal ; beneath this the insect conceals itself. It is 

 rather firmly fixed to the bark by its short rostrum with long flexible 

 setae. The pupal stage is oblong and has transverse brown bars on 

 the abdomen, the wing cases, antennae and legs also deep brown. 

 These give rise to the winged viviparous female, which has a black, 

 shiny thorax, and abdomen ringed and covered with masses of white 

 wool ; the legs are black, and the fuscous wings have coarse brown 

 veins. 



The insects are very harmful when present in large numbers ; 

 the trees should . be sprayed with paraffin emulsion, especially when 

 the larvae are hatching out, and the disease in consequence rapidly 

 spreading. The larvae were very active when the specimen arrived 

 in June. 



This species is often destructive to the Scotch pine (Pinus 

 sylvestris) and Weymouth pine {Pinus strohvs), both on the twigs and 

 trunk. The white flocculent matter is seen in June around the base 

 ■of the needles. There the wingless female produces her yellow eggs, 

 which gradually become brown. 



Numerous natural enemies occur in this species ; the ova are 

 preyed upon, according to Buckton, by the larvae of Scymnus dis- 

 xoideus, and by the Land Bug (Anthocoris fusca, Kalt), and by the 

 larvae of Agromyza chermivora, Kalt. 



