G. S. Graham-Smith 
475 
net is carried inwards and downwards and sewn to the intersecting 
wires, leaving the square area just mentioned uncovered. Over the 
circular hole in the upper piece of wood a balloon trap is fixed, and the 
bait is contained in a shallow earthenware saucer placed in the square 
uncovered area at the base of the trap (Figs. 3 and 5). In these traps 
the bait is exposed in as natural a manner as possible. 
Flies attracted by the bait easily find their way to it, being directed 
by the inward slope of the lower part of the net. After leaving the 
bait they tend to fly upwards and outwards and strike the inner sides 
Kg. 3. Open mosquito-net trap. 
of the trap. The lower inward slope just mentioned prevents their 
finding the entrance, and most of them move up the sides and soon 
enter the ballbon trap. 
Galvanized iron traps, or “tins.” 
This trap resembles one constructed by Prof. C. F. Hodge, and 
consists of a circular galvanized iron box 2 ft. high and 1 ft. in diameter. 
The lid, with a rim 3 inches in depth, projects 2 inches beyond the upper 
margin of the box, and is supported on flanges so that the flies can 
pass up between the rim of the lid and the box and gain entrance into 
Parasitology vm 31 
