PROCEEDINGS OF THE THIRD ENTOMOLOGICAL MEETING 891 



there. At a height of about six inches from the ground-level the entire 

 floor including the walls should have in one complete sheet a layer of 

 reinforced concrete not less than two inches thick. This will prevent 

 termites as well as ants from coming up from below. Above the layer 

 of cement concrete all round the wall on the outside there should be an 

 ant-channel of reinforced concrete, the channel being about 1| inches 

 deep and about 2 inches wide. About 2 inches above the channel a 

 brick should project out of the wall and act as a shade over the channel. 

 The walls of the insectary should be plastered both inside and outside, 

 thus leaving no room for flying queen ants to establish nests in them. 



The plinth of the building may be about 3 feet from the ground- 

 level. The floor should be cemented. The space between the floor 

 and the layer of concrete below may be filled with dry sand. This will 

 afford additional protection against ants and termites and make the 

 floor proof against damp. 



Inside the building the furniture should be plain tables and shelves 

 for rearing cages, etc. It is desirable to have removable tables and shelves 

 which can be taken out and cleaned if silver fish get access and prove 

 troublesome. If water-troughs etc., are required, they should be of 

 reinforced concrete or at least with cemented walls. If brick walls are 

 left unplastered and with siirki or cement pointing dust settles in the 

 chinks and converts them into favourite breeding places of Macraola 

 inquisitrix. Chinks in the walls and tables afford hiding places for the 

 silver fish also. Therefore they should be avoided as much as possible. 



Ants and silver fish are really pests of the insectary. The former get 

 into rearing cages and attack the insects. The latter nibble away dates 

 and records from the cage-slips. Therefore it is necessary to keep both 

 away from the insectary as far as possible. 



As regards the structure of the building, there should be large windows 

 and as many of them as possible. They should all be protected with 

 wire gauze, say of not less than 16 meshes to the inch and provided with 

 flaps on the outside which can be shut when necessary, for instance, 

 against driving rain. When ample ventilation is ensured by the provi- 

 sion of as many large windows as possible— a condition which is present 

 in the Pusa insectary — the temperature inside the insectary does not 

 vary to a great extent from that prevailing outside. Therefore the insects 

 kept in the insectary are not affected to a great extent by the artificial 

 conditions incident to rearing indoors. When this condition is secured 

 the observations recorded in the insectary approximate very closely to 

 those recorded outside. This has been verified in the case of numerous 

 hibernating and a?stivating insects and all stages of them, riz., eggs, 



