Mosquitoes and Gnats. 



573 



it uses as paddles for propelling it through the water. There is no longer an\- 

 air-tube at this end of the Insect, but from the back of the large portion there stands 

 out a pair of curved trumpet-like tubes which serve the same office. The reason 

 for the removal of the respiratory tubes from one end to the other is that this is 

 the part of the chrysalis that comes 

 nearest to the surface of the water. 

 Another reason will appear directly. 



When the wings of the future 

 gnat are formed within the chrysalis- 

 skin, the hind-body is extended and 

 laid along the surface. Then the skin 

 between the two trumpets s])lits and 

 the fore-parts of the gnat emerge. The 

 chrysalis-skin becomes a boat, and the 

 critical operation of emerging from it 

 in an erect position without the use of 

 legs or wings is undertaken. A slight 

 puff of air would blow the gnat over 

 and probably make a fatal ending to 

 the performance. But usually the legs 

 are withdrawn successfully, a pair at 

 the time, and rested on the water ; 

 the wings are spread and dried, and the 

 hind-body is withdrawn from the boat. 

 After a short rest the fully-developed 

 gnat is able to join its companions in 

 flight. But it will be seen that unless 

 the position of the breathing -tubes had 

 been changed when the Insect became 

 a chrysalis, this delicate final meta- 

 morphosis could not have taken place. 



This is the common gnat ol which 

 one or another species is found nearly 

 all over the world, and is the true 

 mosquito. The se.xcs are easilv dis- 

 tinguished by the fact that the female 

 has comparatively simple, thread-like 

 antennse with short side-branches, 

 whilst those of the male are distinctly 

 bushy with frequent whorls of very 

 long branches. The female gnat in 

 preparing for the continuance of the 

 species stands on the water with her fore-legs resting on some slight floating support, 

 and her hind-legs crossed behind her. Into the angle thus formed she deposits lu-r 

 glutinous oval eggs to the number of about a couple of hundred. They all stand 



Photos by] [A. Leal. 



Gnats. 



In these two photographs the distinctions between the sexes are 

 shown clearly. The upper figure is th.it of the male with heavily 

 plumed antemiiE, and longer and more slender hind-body. Thi- 

 comparative simplicitv of the female antennae is evident in the lower 

 figure. The attitude of the legs is not natural, but dictated by thf 

 necessity of getting them into the small field of microscopic vision. 



