84 ANIMAL ACTIVITIES. 
pair of wings, and its mouth-parts are fitted for suck- 
ing. The mouth of the male mosquito is adapted for 
sucking honey from flowers and 
it leads a mild and peaceful life. 
The female mosquito, on the 
other hand, has, in addition to 
the proboscis for sucking blood, a 
number of sharp lances with which 
she pierces the skin of her victim. 
At the time of piercing she also 
injects an irritating fluid into the 
puncture (Fig. 77). 
The music made by the mos- 
quito is produced in two ways, 
first by the rapid movement of 
the wings, and second by the 
passage of air in and out of the 
spiracles. The humming thus 
- made is thought to be heard by 
Fic. 77.—The Mouthof the male mosquito, whose ears 
a Eeinale Mosquila. consist of tufts of hairs on his 
antenne. These hairs are said 
to vibrate in unison with the tones made by the wings 
and spiracles of the female. Experiments seem to 
show that some varieties of mosquitoes are respon- 
sible for spreading both malaria and yellow fever. 
A comparison of the life-histories here outlined gives 
one a notion of the great variety of modifications of a 
common plan of structure to compass different objects. 
How these modifications have come about in the 
progress of insect-life is one of the most interesting 
problems before the student of nature’s ways. The 
change from a caterpillar with biting mouth-parts to a 
butterfly with his long proboscis gives a hint of the 
possibilities of evolutionary growth. 
Questions. 1. Have you observed closely the life- 
history of any insect? If so, what are some of the 
changes you have noticed ? 
