INSECTS AND WAR 27 



series of palmate hairs ; and by its open stigmata 

 or breathing pores, which pierce the surface-film, 

 it puts the interior of the body in connection with 

 the atmosphere. The head is provided on its 

 under surface with two moustache-like structures, 

 which constantly sweep the under surface of the 

 surface-film, sweeping the organic matter which may 

 have floated up from below into the larva's mouth. 

 Since the dorsal surface of the larva is uppermost, 

 and the brushes are on the under surface of the 

 head, when feeding the head is turned round at 

 an angle of 190, and this is done with so much 

 precision that you can almost hear it click. The 

 pupa is also attached to the surface-film by its 

 breathing trumpets, and it is these stigmata, or 

 breathing pores, that are the weak point in the 

 structure of these Diptera, since it is easy by brush- 

 ing paraffin through the water to establish a thin 

 surface-film of oil, which cuts both larva and pupa 

 off from the necessary oxygen, and so kills them. 



Stegomyia, the carrier of yellow-fever, is some- 

 what different in appearance. It is especially 

 a haunter of the dwellings of man, and it fre- 

 quents ships. Its eggs are covered with a series 

 of reticulations containing air which enables 



