20 



THE BOOK OF NATURE STUDY 



utensils, if provided with stagnant water, preferably some of that 

 in which they were found. 



The adult insects are much alike. In common with the 

 true flies, daddy-long-legs, and other gnats, mosquitoes and 

 midges, they have only one pair of well developed wings whence 

 the name " Diptera " (two-winged) for this class of insects. It 

 is the front pair of wings which is functional ; the hind pair 

 being represented merely by two short club-shaped processes, 

 the halteres. The males are distinguishable from the females 

 by their large eyes and by their beautifully plumed antennae. 

 An easy method of discriminating between a culex and a chiro- 

 nomus is afforded by the resting attitude adopted : in culex 

 the hind-legs, but in chironomus the front legs are raised off 

 the ground, as though they were used as feelers. The males 

 of neither kind suck blood ; but the female culex is notorious 

 as a biter, whereas the female chironomus probably never feeds 

 at all, and certainly not on blood. 



The external anatomy of such delicate and small creatures 

 requires so much manipulative skill that we shall here confine 

 our attention to the life-histories. 



Culex. The female culex deposits her eggs early in the 



morning during summer 

 D *^fe>) upon the surface of stand- 



ing water. Using her first 

 two pairs of legs to sup- 

 port her on the margin, or 

 on some floating object, 

 she crosses her long hind- 

 legs, and passes her eggs 

 one by one from the end 

 of the abdomen into the 

 angle between them. At 



FIG. io. A, egg-raft of culex ; B, a single egg ; first the eggS are sticky, 

 C, egg removed from ovary, with bladder-like an so adhere to One 

 appendage ; D, end view of the appendage. , - , . , 



another in a mass which 



gradually causes the hind-legs to move wider apart. At 

 length some two hundred or three hundred eggs are fastened 



