DRAGON FLIES AND MOSQUITOES 165 
he asserts that “no Anopheles larva has a chance in any bit of water inhabited 
by them. . . . Their surface habit and their tendency to get near the edges 
make them especially dangerous to Anopheles larve, which absolutely fail to 
maintain themselves within the range of these beetles.” The larve of the 
Gyrinide are also predaceous but live at the bottom and no observations of their 
preying upon mosquito larva have come to hand. 
Dr. Eysell dwells upon the efficiency of aquatic Hemiptera as mosquito de- 
stroyers. He states that of the forms living beneath the water Nepa, Ranatra, 
Naucoris, Notonecta and Coriza destroy great numbers of mosquito larve. The 
forms living upon the water-surface, like Limnobates and Hydrometra, destroy 
emerging imagos or females in the act of depositing eggs. 
In German New Guinea, Drs. Dempwolff and Wendland, in the course of 
their malaria work, found that waters which contained many Notonecta har- 
bored no mosquito larve. This led them to introduce these insects into the 17 
water-tanks of-an European settlement with the result that within a week the 
mosquito larve had all disappeared from the tanks and the number of mosquitoes 
inside the houses was considerably diminished. Further experiments with 
Notonecta, initiated with mosquito-breeding pools, gave no practical results on 
account of the rapid drying up of the pools. 
Doctor Smith also gives observations upon several aquatic bugs, indicating 
that Notonecta, Nepa, and Ranatra are effective enemies of mosquito larve but 
that, owing to the fact that they occur chiefly in permanent waters, their use- 
fulness is restricted. He quotes an interesting observation by Mr. Viereck, as 
follows: 
“The early stages of Ranatra fusca were destructive to wrigglers. With 
their raptorial legs they nip the larva near the breathing tube, then either drop 
or suck it. Quite a number were nipped and dropped, and, once dropped, they 
rose no more. Pupe, both of Anopheles and Culex, were expert in evading the 
grasp and were not readily caught. In less than an hour three Ranatra killed 
and sucked ninety-eight larve. It is a question whether Ranatra would be use- 
ful in stagnant pools, because the specimens used in the experiment could only 
be found in the clear water of a lily pond where, no doubt, they controlled the 
Anopheles; but when put into the stagnant water which sollicitans inhabits, 
they died.” 
Dragon flies feed upon flying mosquitoes, and their larvee feed upon mosquito 
larve and pupe. This propensity of dragon flies is so well known that in some 
sections of the country they are popularly termed mosquito hawks. The late 
Dr. R. H. Lamborn, of New York City, was so impressed with the voracity of 
dragon flies, from observations made while engaged in railroad building in the 
swampy forests around the head of Lake Superior, that, in 1889, he offered three 
prizes for the best essays on the mosquito and the house fly. These essays were 
to include observations and original investigations regarding methods of de- 
stroying the mosquito and the house fly, observations and experiments to best 
accomplish the artificial multiplication of dragon flies to breed them in large 
numbers, and to include an estimate of the cost of producing them by the 
thousand. How feasible his plan seemed, not only to himself, but even to as 
