Mr Edwards, On the Procession and Pupation, etc. 431 



On the Procession and Pupation of the Larva of Cnethocampa 

 pinivora. By T. G. Edwards, B.A., Emmanuel College. (Com- 

 municated by Mr H. H. Brindley.) 



[Bead 21 February 1910.] 



The following note is a summary of certain observations made 

 during a fortnight spent at Arcachon, between the 18th and 31st 

 of March, 1909, a visit which I undertook at the suggestion of 

 Mr Brindley with a view to clearing up certain points with regard 

 to the processional larva of Cnethocampa pinivora. 



The habits of this peculiar larva were first studied by Reaumur 

 in 1736, who treated the subject in considerable detail; but as his 

 material was all conveyed by coach from Bordeaux to his house at 

 Paris, the conditions under which his experiments were performed 

 were necessarily somewhat artificial. Ratzeburg also described 

 the life history, while in the last fifteen years Fabre has recorded 

 his observations on all stages of this moth, confirming many of 

 Reaumur's results and adding much to his account of this insect. 

 Lastly, a paper by Mr Brindley appeared in the Proceedings of 

 this Society for 1906. In this was given a detailed account of the 

 behaviour of a certain procession which came under the writer's 

 observation, together with certain other points which supple- 

 mented Fabre's description. 



On warm days in March and April the processions of Cnetho- 

 campa pinivora are frequently to be observed in the neighbourhood 

 of the Pine Woods of the Landes, where their nests form prominent 

 objects among the branches. 



The procession is one of single file, the larvae being arranged 

 in head to tail contact. The whole moves along a silken thread 

 which is commenced by the leader and added to by all the larvae 

 in succession. 



The number comprising a procession varies greatly, and though 

 I saw many processions, I only encountered three which exceeded 

 one hundred in number. The largest of these was crushed upon 

 the pavement of a road near the woods, but it measured 26 ft. and 

 must have contained at least 260 larvae. 



Nature of the Procession. 



(a) Priinite. Several experiments were made with a view to 

 determining how far the primite may be regarded as the true 

 leader. It was found — as Fabre states — that any larva could 

 function as primite, and that all individuals in the procession 



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