Our common mosquitoes belong to three genera, _Culex_, _Anopheles_ and _Corethra_. The annoyance caused by the irritation resulting from the bite is not understood, as no poison gland has been found. The females only of our mosquitoes are known to suck blood. From researches made during the past few years it is now definitely known that the bite of certain kinds of mosquitoes is really dangerous. This is not on account of the actual puncture made by the insect, but due to the presence of the germs of malaria, which are introduced into the wound from the infected insect. The only mosquitoes which are definitely known to transmit this malarial parasite to man belong to the genus _Anopheles_. The malarial parasite thus has two hosts, mosquitoes belonging to the genus _Anopheles_ and man. This parasite infests the stomach walls of the mosquito, where it rapidly multiplies and becomes mature; then escaping from this locality, accumulates in the salivary glands. From this reservoir they are easily transferred to their human host at the time of sucking blood. These aquatic insects which we have discussed so briefly are only a few samples from a very large number whose history and habits are full of interest to those who find the study of animal life a fascinating subject. INSECT MUSIC. The peculiar sounds made by different insects, though usually known as insect music, are probably far from musical in the opinions of those who listen to it with dread. Many superstitious people have firm belief in dire warnings concerning certain calamities which "insect music" portends. For instance we are told that the "deathwatch" is a popular name applied to certain beetles which bore into the walls and floors of old houses. They make a ticking sound by standing on their hind legs and knocking their heads against the wood quickly and forcibly. Many superstitions have been entertained respecting the noise produced by these insects, which is sometimes imagined to be a warning of death. There are many insects, however, which produce sound decidedly musical; and many such instances have been enumerated. Everybody is familiar with the music of the katydid. Here it is the male that has the voice. At the base of each wing cover is a thin membraneous plate. He elevates the wing covers, and rubs the two plates together. If you could rub your shoulder blades together you could imitate the operation very nicely. Certain grasshoppers make a sound when flying that is like a watchman's rattle--clacketty-clack, very rapidly repeated. There are also some moths and butterflies which have voices. The "death's-head" moth makes a noise when frightened that strikingly resembles the crying of a young baby. How it is produced is not known, though volumes have been written on the subject. The "mourning cloak" butterfly--a dark species with a light border in its wings--makes a cry of alarm by rubbing its wings together.