Outdoors, Tabanids or horse and other flies in great variety make life miserable in the woods or on the sea-shore, while even in New Jersey an occasional mosquito may yet be met with, ready to demonstrate that he likes you none the less because of 
Fig. 2. A horse-fly—Tabanus atratus; a, larva; b, pupa; c, adult; after Riley. any campaigns waged against him—or her.
Gnats and midges of various kinds, whether we call them black-flies, punkies or other names, all manifest an affectionate interest in the human visitor to their homes, and I do not mind saying that there have been occasions when I abandoned the field to them and admitted defeat. It is wonderful how well fitted these insects are for their work and how well they understand the use of the tools with which kind nature has provided them!
Some kinds of insects have no grudge against man and as such never bother unless interfered with, but they are quite ready to manifest their displeasure if they are wasps or hornets, or to make it unpleasant in other ways to the ignorant meddler, as in the case of many of our Limacodid larvæ or nettling caterpillars. Sometimes an insect becomes a nuisance quite without intent, as in the case of the caterpillar of the brown-tail, which distributes its hair so liberally that it produces severe irritations and inflammations, as those residents of Massachusetts 
Fig. 3. The saddle-back caterpillar, a, from above, and b, from side; after Riley. that have suffered from "brown-tail rash," know to their sorrow.
And this brings me, naturally, to the consideration of those forms that are troublesome or even dangerous to man because they are agencies in the transmission of diseases, either as carriers or as intermediate hosts. Note that I use two terms; carriers and intermediate hosts, because there is a vast difference between them. Carriers are such insects as merely pick up by accident disease "germs"—to use a current expression—and transport them to another place where they may or may not
