r. 
and thorax are_ fused into a mass, ou the under side of 
which depend the rudiments of the wings, legs, and pro- 
boscis, while from the dorsal side project a pair of funnel- 
shaped breathing organs ; the terminal segment of the abdo- 
men bears a pair of swimming-plates. In the case of Gnlex 
the larvae and pupae are exceedingly active, moving about in 
the water by a jerking or wriggling motion of the body ; 
they are under the necessity of coming to the surface to 
breathe at frequent intervals. The larva of Anopheles is more 
sluggish, and its habit is to float horizontally at the surface 
of the water. 
In the case of Culex pimgens, Wied., a common North 
American species, it was found by Howard (op), cit., p. 14) 
that the minimum time occupied by the whole life-history 
cycle was ten days — ‘‘ namely, sixteen to twenty -four hours 
for the egg, seven days for the larva, and two days for the 
pupa.” But the period necessary for a generation “ is almost 
indefinitely enlarged if the weather be cool,” so that it is also 
permissible to suppose that it is accelerated by heat. 
In the perfect state, Howard found that the male insects 
died qi\ickly in confinement, but that the females were much 
longer-lived, some even existing without food for three 
weeks.* In cold climates large numbers of the perfect 
insects pass the winter in a state of hibernation. 
List of Articles Required for Collecting’ and Pre- 
paring- Mosquitoes. 
One entomologist’s collecting-net of book-muslin (one or 
two spare net-l)ags should be taken in case the one in use 
gets torn). 
One dozen gl^HB-hottomed pill-boxes (H to Sin. in diameter 
is about the best size). 
* In Queensland Dr. T. L. Bancroft has kept a certain species of Culrx 
alive for 70 days in confinement. 
