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THE POPULAR SCIENCE MONTHLY 



Fig. 2. A horse-fly — Tabanns atratus ; a, larva 

 b, pupa ; c, adult ; after Riley. 



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 demon- 

 strate that he likes you 

 none the less because of 

 any campaigns waged 

 against him — or her. 



Gnats and midges of 

 various kinds, whether we 

 call them black-flies, pun- 

 kies 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 ad- 

 mitted 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 larvas or nettling caterpillars. Sometimes an insect be- 

 comes 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 

 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 danger- 

 ous 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 



Fig. 3. The saddle-back caterpillar, 

 a, from above, and b, from side ; after 

 Riley. 



