682 THE POPULAR SCIENCE MONTHLY. 



Macauley, U. S. Army, relates that, in a mosquito-infested region 

 of Montana, he was told how the mosquitoes had disappeared, as 

 if by magic, on the sudden appearance of a brood of devil's-darn- 

 ing-needles or dragon-flies of rather large size. The agency of 

 this insect in the matter was corroborated by the evidence of 

 squaw-men and Indian traders, who said that the flies did not ap- 

 pear every mosquito year, but, when they did, they came in droves 

 and cleared the mosquitoes out. They were called "mosquito- 

 hawks." The captain himself afterward had an opportunity of 

 observing them at work, and to determine that they were dragon- 

 flies. " I noticed," he says, " that they flew in an irregular kind 

 of skirmish-line, moved slowly, and every now and then made 

 what he described as short l dabs ' at apparently nothing. Mr. 

 Heistand said that ' each one of these dabs means a mosquito.' I 

 was curious to see how deliberate they were about it, and how 

 fairly aligned the skirmish-line was. They appeared somewhere 

 about 11 a. m., and when I went into the post later I crossed the 

 parade-ground and saw detachments of about half a dozen flying 

 slowly about. They stayed at about an average of three feet from 

 the ground. I do not know how late they kept it up or how early 

 they began. They stayed until all the mosquitoes appeared to be 

 gone." Dr. Lamborn also tells how his own attention was drawn 

 to the subject. It was while he was in the forests of Lake Supe- 

 rior, railroad-building. " Sitting in camp while supper was being 

 prepared, I often, with a sentiment of gratitude, looked through 

 my mosquito- veil at the dragon-flies that collected in the open 

 spaces among the pine-trees. They darted from side to side like 

 swallows in a meadow, but with amazing rapidity, and at every 

 turn, the natives assured me, ' a mosquito ceased from troubling/ 

 Afterward I happened to observe an entomologist feeding a 

 dragon-fly that had eaten thirty house-flies in rapid succession 

 without lessening his voracity. What thought could be more 

 natural than the one that came to me, that an artificial multipli- 

 cation of dragon-flies might accomplish a mitigation of the mos- 

 quito pest ? " 



Mr. Beutenmuller, of the Museum of Natural History, New 

 York, avers that "the dragon- flies (Odonata), especially the 

 JEscliinus, Gomphina, and Libellulina, are the natural enemies 

 of the mosquitoes ; they are voracious — they sometimes appear in 

 great numbers, and, as a matter of fact, the mosquito disappears 

 before them, while their breeding-grounds are, in many respects, 

 similar, so far as fresh and brackish water habitats are concerned ; 

 and, finally, in the metamorphosis of the dragon-fly we meet con- 

 ditions which introduce it in antagonism to the mosquito at the 

 same stages of development." The dragon-fly, however, prefers 

 sunlit areas, and will not live in the woods. 



