INSECTS AND DISEASE. As annoying man him self, insects play an important part, since there are very few regions of the habitable globe where man is not troubled by them. Bedbugs, fleas, lice. the itch-mite, the screw-worm fly, mos quitoes (qq.v.). and many other species unite in this method of damage to the human species. It is, however. as carriers of disease that insects are perhaps of the greatest. importance in their rela tions to the human species. The filaria diseases of the East (elephantiasis, chyluria. and lymph scrotum) are transferred by certain mosquitoes; the Texas fever of cattle in the United States, the red-water diseases of Africa, and other cattle fevers are transmitted by certain ticks; the tsetse-fly of Africa carries the micro-organisms of disease; the purulent conjunctivitis of the Egyp tians and Fiji Islanders is communicated by the house-fly; the eye disease. known as 'pinkeye' in the Southern United States, is transported by minute flies of the genus Ilippelates. Asiatic cholera and typhoid fever are carried by the house-fly; and it is claimed that the bubonic plague is spread by fleas. All forms of malaria are carried about by mosquitoes of the genus Anopheles (see MosQuITo), and yellow fever by those of the genus Stegomyia. (See Mosqurro.) It has also recently been claimed that dengue fever is in Syria spread by a mosquito of the genus Culex; that Anthrax bacilli in malignant pustules in human beings are caused by the bite of flies of the genera Tabanus and Stornoxys; and that the famous `surrale disease of cattle in Oriental regions is also carried by gad-flies.
POlSONOCS INSECTS. Certain insects may be considered under this head which poison human beings in any one of several different ways: (1) They may have a sting which is a modified ovi positor, and which is connected with a specific poison-gland, as with the bees, wasps, stinging ants, and certain other Hymenoptera. (2) There may be a modified salivary gland which has a poisonous secretion and is connected with a piercing beak, as with certain bugs of the order Heteroptera, and as with many dipterous insects like mosquitoes and other biting flies. (3) The hairs covering the body surface may be modified into sharp bristles, which may be simple or barbed, and which, when coming in contact with the skin of human beings, produce an urticating or nettling effect. Poisonous insects of this group are confined to the caterpillars or larvae of cer tain moths, especially of the family Limacodithe, and, to a much less marked extent, a few of the caterpillars of Bombyciche. such as Orgyia leuco stigma, Euproctis as well as to a few of the Saturniida% like the larva of the Io moth. (4) Certain beetles when crushed pro duce a blistering effect upon the skin. These are confined to the family Meloithe or blister beetles (q.v.).
The poison of bees is formed by the mixture of the secretions of two glands. one of which is
acid and the other alkaline. With the burrowing wasps the alkaline gland is absent or atrophied, and the poison consists only of the acid. The effect of the sting of these wasps is to stupefy the prey and not to kill it. It results that the insects stung remain in excellent condition as food for the lame of the wasps for a considerable length of time. (See Wasp.) The severity of the sting of the aculeate Hymenoptera and the amount of poison injected into the wound differ with different species. The sting of our large mud-wasp (q.v.) is especially severe, and as a rule the stings of wasps have a more poisonous effect upon human beings than the stings of bees. There are cases on record where many bee-stings on the same individual have produced death. Several instances have been well authenticated by medical men of the death of a human being from a single sting of a wasp. the sting acting as a very powerful irritant poison on the nerve centres of the patient. As a rule such eases are confined to exceptionally nervous individuals. to those inheriting gouty tendencies, who are remarkably susceptible to the action of certain medicines. Persons handling bees and wasps be come immune to their poison : the stings have little effect upon them. This immunity. however. disappears in the absence of continuous rein °ciliation. This fact is well known to bee keepers. and entomologists who collect wasps and other stinging Hymenoptera in large numbers have called attention to the same fact. The rem edv for the stings of both bees and wasps is the immediate application of an alkali.
Many of the poisonous flies are treated. of undur alostitiro: GAD. FIN ; and lif.ack-Fts 'Flue true bugs which give a poisonous bite with piercing beak, and which may attack man, be long almost entirely to the family R•thivikhe (see ('oNF:xosE), to which the terms 'pirate bugs' and 'kissing lungs' are applied. The Eastern species are tips vs tor hedurins) /a. rso I us, ihrignolt.st( s picipcs, and .1)clui n9Irstcs Iniumi nulls ; and tile principal Southern mid Western forms are Rasa II us b i yu tat us and I 'onorliin us su rum is lig us. (Sie the article Co N E NOSE.) The bite of these hugs is specifically poisonous, but the great inflammation which so often occurs is doubtless due to the entrance into the eir t ion of germs of putrefaction, since the bugs are attracted to dead animal matter. The Eastern species ( Mcianotextes picincs) is a shin ing black bug rather more than a half inch in length. The principal Western species (llohasus biyuffotus) is reddish in color with blue black fore wings. each marked with a round reddish spot. This latter species is, according to David son. the cause of nearly all of the supposed eases of 'spider bites' in the