A CONTRIBUTION TO THE LIFE-HISTORY OF THE 

 LARCH CHERMES [CNAPHALODES STROBILOBIUS, 



KALT.y. 



By EDWARD R. SPEYER, F.E.S., M.A. (Oxon.), 

 Carnegie Scholar. 



Formerly Lecturer in Economic Entomology at Oxford University 

 and Tutor in Zooloyy to University College and N on- collegiate 

 students. Recently special Entonwlogist and Acting Entomologist to 

 the Government of Ceylon. 



(\\ itli Diagraui and Plates VI and VII.) 



INTRODUCTION. 



The insect commonly known as Larch Blight from the conspicuous 

 white "wax-wool" which it secretes on the leaves of this tree during the 

 spring and summer months, possibly has the most complex life-cycle of 

 any member of the family Chermesidae. The Genus Chermes was 

 established as such under the family Phylloxeridae, and in course of 

 time, with the increasing discovery of species, became included in a 

 Sub-family Chermesinae, containing several Genera, and finally in a 

 family, embracing the Sub-families Phylloxerinae and Chermesinae. 



There may be justification for this, but it is suggested that such a 

 classification is a little premature, considering that the Sub-family 

 Chermesinae comprises as many as seven genera, containing altogether 

 only about twenty species. 



Further, as an example, the Genera Chermes and Cnaphalodes have 

 been differentiated through petty structural and morphological char- 

 acters, which pale in the face of the greater and more prominent differ- 

 ences in habit and structure of the various generations of a single species. 



Finally, these genera have been founded without any reference to 



^ The greater portion of tliis Paper is the result of an investigation made for the 

 Delegacy of Forestry at Oxford University in 1913 and 1914. A report, embracing the 

 material in detail, was submitted to the Delegacy in June, 1914, but does not appear to 

 have been published. 



12—2 



