j2 Mosquitoes 



obtaining floating matter, he therefore but proves 

 the rule. 



The bottom feeders go rooting in the mud and de- 

 bris at the bottom, or nibbling over the sides of a tank, 

 or of half submerged objects — grasses, Spirogyra, 

 etc. These forms have rather stubby hairs on the 

 maxillae. The antennae are stumpy and straight, with 

 small tufts and terminal spines; long ones would be 

 in the way in grubbing. O. dnpreci, with its very 

 short antennae and bottom feeding, is a good exam- 

 ple ; also O. triseriatus, which eats at the bottoms 

 of tree hollows. There are maxillae (never mandi- 

 bles) which seem transitional, as in O. atropalpus ; in 

 these forms the larvae brush submerged objects for 

 protococci and take in considerable floating matter, 

 rather than dig. As to whether larvae aid much in 

 purifying water is very uncertain. 



Other Structures and their Uses. — It might be 

 interesting here to note some of the different adap- 

 tations and modifications of other larval structures. 

 The hairs on the head and body are sense organs 

 of some sort ; I think that the unfringed ones are 

 tactile ; the fringed hairs perceive direction and 

 vibration (are practically auditory). Perhaps the 

 tufts on the sides of the thorax in the forms which 

 feed below the surface are also a help in balanc- 

 ing. On the thorax of MegarJiinus many of the 

 tufts are converted into large stiff spines with 

 spinules: these may be more or less of a protection. 

 The stellate hairs in Anopheles undoubtedly catch 

 in the surface film, thus supporting the larva in the 

 horizontal position which is necessary for its custom 



