THE ORDER DIPTERA.
This order includes all the true flies or insects having but two wings. There is probably no other order of insects that are more injurious to the health of human beings. The housefly, because of its habits, is a virulent pest in the spreading of disease and it has been discovered that certain mosquitoes carry the germs of malarial and yellow fevers.
Mosquitoes.
Up to the year 1900 little had been known about these insects. Since then it has been discovered that one genus is responsible for the transfer of malarial fever and another variety is the sole means of the spreading of yellow fever. Mosquitoes are found in any locality where stagnant standing water allows them the opportunity to breed. Their eggs are laid in a flat mass on the surface of the water, and each of these masses contains from 200 to 400 eggs. The young mosquitoes issue from the under side of the eggs, coming to the surface frequently to breathe, which they do by means of a long tube at the end of the body which is thrust up above the surface of the water. In many localities boy scouts have been interested in exterminating mosquitoes, the most successful methods being either the abolition of their breeding places, the flooding of surfaces of stagnant water with kerosene, or the introduction of fish into fishless ponds. In a mosquito crusade every receptacle for standing water must be found and either destroyed or treated with kerosene.
Midges.
Midges are small or minute flies; swarms of them are commonly seen in damp localities in the summer.
Flies.
Horseflies are unusually abundant in the neighborhood of ponds and streams.
The Robber Flies, or bee-killers, are the hawks of the insect world, preying upon their victims on the wing. In flying an insect is likely to become the victim to their sharp little dagger, which they carry in their beak. It is said that they will frequent a favorite position near a beehive and make frequent trips back and forth, and hundreds of empty bodies of bees are found beneath this perch.
The Dancefly is so called because of the up-and-down movement which they make in their swarms.
The Housefly. These insects are highly injurious to human beings because of their agency in spreading germs of such diseases as typhoid fever and Asiatic cholera. It has been discovered recently that germs of infantile paralysis are conveyed by the housefly.