ENTOMOLOGY IN OUTLINE DIPTERA. 89 



blood-sucking propensity of the mosquito family is an acquired taste, for 

 while all that can, absorb our blood with that of other warm-blooded 

 animals, they breed in countless billions in swamps and marshes, far 

 from any warm-blooded animals, and there they live and die without 

 tasting blood. 



The mosquito breeds in water, and the so-called wigglers" found in 

 stagnant pools are the young form or larvae. While aquatic in their 

 mode of life, these larvae are air-breathing, and have to come to the 

 surface for a supply of air. For this reason they frequently come to 

 the top, stick out their breathing apparatus, which is a sort of tail-like 

 tuft, and after absorbing the supply of air, disappear in the depths of 

 their breeding-pool again. It is for the reason that the larvae are com- 

 pelled to come to the surface to breathe that pouring coal oil over stag- 

 nant pools will keep them down and is the most effective remedy for 

 this evil. 



The family Chironomidse are the true midges, small mosquito-like 

 insects. They differ from the former family in their wing markings 

 and habits, not being addicted to blood sucking. Sometimes they are 

 so numerous as to be annoying, but otherwise they are neither good 

 nor bad. 



The family Myeetophilidse consists of small to medium insects, gen- 

 erally resembling the mosquito in structure. The larvae live upon 

 fungi and decaying vegetable matter. 



The family Ceeidomyiidse, the gall-gnats, are small insects, including 

 the smallest of this order. Their common name indicates their habits. 

 Many of them are very serious pests to the farmer, for in this family 

 are many which attack crops, as the clover-leaf midge and the wheat 

 midge, both of which do great damage to crops, and here we have that 

 worst of all grain pests, the Hessian-fly. It is impossible to accurately 

 estimate the amount of damage actually inflicted upon our farmers 

 annually by this pest, but it runs into the hundreds of millions. For- 

 tunately the wheat-growers of California have not been troubled much 

 by this insect, due, probably, to the habit of burning over old stubble in 

 the fields, by which means the eggs are destroyed. 



The Rhyphidse, the false crane-flies; the Orphnephilidse, the solitary- 

 midges; the Bibionidse, the March-flies; and the Simuliidse, the black- 

 flies, are all families of little importance except to the entomologist. 



The family Tabanidse includes the horse-flies. These are well known 

 and are one of the worst pests of our domestic animals during the 

 summer season, when they sometimes attack horses in swarms and 

 cause them much trouble. These insects have such sharp mandibles 



