892 PSOCEEDINGS OF THE THIRD ENTOMOLOGICAL MEETING 



larvae, pupae and adults, which have been kept under observation both 

 in the insectary and outside in the fields. In the Plains of India it is 

 not necessary to have the conditions of a green-house or glass-house for 

 rearing insects. Nor should there be any discrepancy between observa- 

 tions carried on in the insectary and those, under actual field conditions. 

 When however no separate insectary is built it is preferable to carry 

 on rearing in the verandah of a house. The verandah can be enclosed 

 with wire gauze and in order to prevent ants the legs of rearing tables 

 can be placed on ant-proof stands as shown in PI. 138. fig. 2. The stands 

 may be of wood or stone and the channels in them should be kept filled 

 with water or phenyle water to prevent ants crossing the water or mos- 

 quitos breeding in it. 



55.— BEEEDING CAGES AND GENERAL INSECTARY TECH- 

 NIQUE FOR WOOD-BORERS. 



By C. F. C. Beeson, M.A., I.F.S., Fmest Zoologist. 

 (Pis. 139— 140.) 



When the study of the wood-borers of valuable forest trees was 

 commenced a few years ago at Dehra Dun, it soon became evident that 

 one could not isolate the important species and investigate their life 

 histories as separate items of research. The borer fauna of a forest tree 

 is a complex association of species from several families of Coleoptera, 

 e.g., Anthribidse, Scolytidae and Platypodidae, Ciu-culionidse, Ceramby- 

 cidse, Lamiadse, Buprestidse and Bostrychidse, with occasional species 

 of Cossidse, Arbelidae and Hepialidse. The proportions in which the 

 species occur in a particular tree are influenced primarily by the time of 

 year at which the tree dies and the time of occurrence of the swarming 

 periods of the beetles, that breed in it. It is possible, for example, 

 for the available bark space of a dying or recently dead tree to be occupied 

 by surface breeders such as bark beetles, Buprestids, small Longicorns, 

 etc., to such an extent that heartwood borers and shothole borers are 

 unable to effect an entrance and establish their galleries. Or it is possible 

 for a large Longicorn to arrive first on the scene and monopolize the 

 sapwood to the exclusion of small shothole and pinhole borers, etc. 



As a check on field work it was decided to breed out the borer fauna 

 on a large scale in the insectary at Dehra Dun, and to correlate the emer- 

 gence records so obtained. The usual procedure followed is to fell 

 selected trees in forest divisions at intervals throughout the year, and to 

 cut off lengths from the felled trees at one month or two month intervals 

 and rail the logs to Dehra. 



