890 PEOCEEj)INGS OF THY. TUIKD ENTOMOLOGICAL MEETING 



is filled with earth up to the height of the brick walls. The earth 

 is watered as necessary and remains moist throughout the year. At 

 first only two of these cages had cemented bottoms. Termites, crickets 

 and even beetles often appeared in the other cages which had no cemented 

 bottom and therefore commmiicated with the soil below. All the cages 

 have now been provided with cemented bottoms. They do not communi- 

 cate with one another but each has a panelled door fitted with glass panes 

 and opening into the hall. 



Insects are sent in to Pusa from various places in India and as some 

 of them may not occur in the neighbourhood of Pusa or in Northern 

 India, the Pusa lusectary, in which they are intended to be reared, is 

 built on a plan which prevents their escape from confinement even if 

 they escape from the rearing cages. The doors and windows are pro- 

 tected with wire-screen havmg about 12 meshes to the inch. This is 

 not fine enough for very small insects. But no case of introduction of 

 an undesirable insect into the locality has happened during the last 

 fourteen years. With the same object in view the outer doors are pro- 

 vided with double flaps, the outer pair of which is of wire gauze 

 (PI. 137, fig. 2) ; one pair of these flaps can be shut before the other 

 pair is opened ; thus the entrance of any insect from outside or 

 the escape of any from inSide can be checked. This is satisfactory 

 so far as flymg insects or large creeping ones are concerned but 

 is no protection against small creeping ones. In fact, ants are a 

 trouble throughout the hot weather and the rains. In order to prevent 

 them an ant-channel of re-inforced concrete was added all round 

 the wall at a height of about a foot from the ground. The channel is 

 about one inch deep and is kept filled with water mixed with phenyle 

 or crude oil emulsion. In order to prevent leaves and grasses being 

 blown into the channel and aft'ording bridges for ants to cross over it was 

 necessary to have a shade of galvanized zinc sheet (see PI. 137, fig. 1) 

 over it. The ant-channel works satisfactorily. But as the floor was 

 of bricks set on edge and not of concrete, ants were able to come up 

 anywhere in the floor from below the foundation. In order to 

 prevent this the floor has recently been concreted. Still, however, we 

 have not been able to get rid of ants altogether. The walls, not 

 bemg plastered from outside, ants have found enough room to 

 estabhsh nests in them. 



When future insectaries are built, in order to make tlieni really ant- 

 proof the following arrangements illustrated in PI. 138, fig. 1 might be 

 tried. All round the building at about the ground level there should 

 be a cemented pucca drain which may be a shallow one. This will prevent 

 water settling at the fomidation and also ants from establishing nests 



