9 o THE ANIMALS AND MAN 



body? Note the indications of legs and wings folded on 

 the under side of the head end. Make a drawing showing 

 and naming these parts. 



In two or three days the pupa suddenly changes into the 

 full-fledged winged mosquito. That is, the cuticle or outer 

 skin wall of the body splits along the middle line of the 

 back, and the winged mosquito emerges through this open- 

 ing. What part of the body appears first? What parts 

 next? While the mosquito is emerging the pupal skin 

 serves as a raft upon which the soft-bodied damp insect is 

 partly supported until its wings and legs are unfolded and 

 dried and hardened, and it is ready to fly away. Some- 

 times the body rests simply on the surface of the water, 

 being supported by the surface film. This transformation 

 of pupa into fully developed mosquito can be readily ob- 

 served, and each pupil should see it. 



The winged or imago stage.- -The mosquito is now 

 full-grown and fully developed; and in this fully developed 

 stage it is called an imago to distinguish it from larva and 

 pupa. It is of course the same insect, a mosquito all the 

 time, but we commonly apply that name only to the winged 

 stage or imago. A few of the winged mosquitoes should 

 be killed in a "killing-bottle" (see Appendix I), and examined 

 under a hand lens. Two kinds may be distinguished; 

 one with many long hairs on their feelers or antennas, the 

 other with fewer and much shorter hairs; the latter are 

 females, the ones with bushy antennas males. These 

 antennae are the mosquito's organs of hearing. How many 

 wings has the mosquito? How many pairs of legs? Can 

 you find behind the wings a pair of delicate little knobbed 

 processes projecting from the body? These are called 

 balancers and they aid the mosquito in directing its flight. 

 Note the long, piercing and sucking beak (fig. 37) by means 

 of which the mosquito gets its food, which is either the blood 

 of animals or the sap of plants. The male mosquitoes 



