Many mosquito species rest amongst grassy and shrubby
vegetation and on the foliage of bushes and shrubs. Mosquitoes have sometimes been collected by slowly walking through vegetation and capturing
them in small hand-nets as they are disturbed and fly out (McClelland 1957;
McClelland and Weitz 1963; Teesdale 1959). McClelland (1957), however,
realised that this procedure was likelyto be biased in favour of collecting
unfed females of species that bite man,because having been disturbed they
will tend to be attracted to the collector. In one series of catches in East
Africa the catchers used an insect repellent (dimethyl-phthalate) to try and
prevent unfed females of Aedes aegyptibeing attracted to them after they
had been disturbed from their day-time resting sites (McClelland 1957).
In the USA Copeland (1986) caught adults of Ochlerotatus thibaulti
from a wood by disturbing vegetation witha stick and collecting them with
a sweep-net. He also used two green resting boxes, but most adults were
collected with mechanical aspirators(Nasci 1981). In South Africa mosquitoes that were flushed out by walking through grassy vegetation were
caught in test tubes as they resettled on nearby vegetation (De Meillon
et al. 1957).
Some species may not be readily flushed out by walking through vege