54 
IMPORTANT AND FAMILIAR INSECTS 
battle starts they send out scouts. They await the return of 
the scouts before they begin the battle. 
7. When one colony subdues another in battle, the victors 
take home the larvae and pupae of the vanquished and bring 
them up to be slaves. The slaves seem to be loyal to their 
conquerors and to take great interest in the welfare of the 
victorious colony. 
8. Among certain kinds of ants the slaveholders have 
depended so long on the slaves that they are unable to build 
nests or even feed themselves. If the slaves are taken away, 
the slaveholders starve. The slaveholders are able to fight, 
however, to get more slaves. 
35. Diptera. — The Diptera (dip'ter-a : Greek, di -, two; 
pteron, wing) include such harmful insects as the mosquito, 
house-fly, bot-fly, and cheese-skipper; 
also the beneficial bee-fly, wasp-fly, 
and tachina-fly. 
One of the most important members 
of this group is the common mosquito, 
which lays from two hundred to four 
hundred eggs in a raft-like cluster on 
the surface of the water in any stag¬ 
nant pool or rainwater barrel. These 
eggs are usually laid early in the 
morning and, in favorable weather, 
hatch the afternoon of the same day. The wigglers (larvae) 
keep to the surface when breathing but swim freely in the 
water for food. Food is brought to the mouth by vibrating 
cilia, which keep a current of water passing near them. 
From this water the wiggler collects his food. After seven 
days of this life it becomes a pupa, which, unlike most other 
pupae, can move about. The pupae remain at the surface of 
the water for air but descend by swimming when disturbed. 
The pupa stage lasts for two days, when the adult emerges 
and flies away after its wings are dried. 
Figure 45. — Common 
House-fly. 
