140 



THE GUIDE TO NATURE 



Insects that Swim under Water. 



Professor C. R. Crosby, of Cornell 

 University, recently discovered an in- 

 teresting insect {Caraphractus ductus 

 Walker) that swims under water in the 

 adult or imago stage, by the aid of their 

 wings. He says : 



"The adults of this species seem per- 

 fectly at home under water and swim 

 quite rapidly by means of their wings 



THESE INSECTS ARE AT HOME UNDER WATER 

 AND SWIM BY MEANS OF THEIR WINGS. 



with a jerky motion, corresponding to 

 the wing strokes made at the rate of 

 about two per second. The legs are 

 trailed behind and are not used in 

 swimming. They spend much of their 

 time walking nervously over the stems 

 of submerged plants, the surface of 

 which they examine carefully with the 

 tips of their antennae, as if searching 

 for eggs in which to oviposit. They 

 are able to walk on the sides of the 

 glass aquaria and on the under side of 

 the sm-face film. After transferring 

 a jar of water containing these para- 

 sites from one building to another a 

 number were found on the upper side 

 of the surface film in the air and flew 

 across the surface trailing their legs 

 attached to the film. They emerge from 

 the water by crawling up some object 

 and forcing their way through the sur- 

 face film. 



"We have been vuiable to see any ex- 

 ternal air supply carried by these 

 insects while under water. While sub- 

 merged they appear to be perfectly 

 wet but as soon as they emerge into the 

 air they seem to be perfectly dry. They 

 are able to live submerged in water for 

 over 12 hours in a bottle filled full of 

 water and corked." 



This is practically the same as Poly- 

 nema nataiis about which Lubbock of 

 England published fifty-two years ago. 

 Quite a number of aquatic insects can 

 fly in the adult stage, but do not use 

 their wings for "flying" through water. 

 They swim by aid of their flattened 

 legs. 



Can any of our readers give informa- 

 tion of any other insect that "flies" 

 under water? 



A Killdeer Assists a Farmer. 



Stamford , Connecticut. 

 To the Editor : 



A killdeer, or ring-necked snipe as it 

 is called on the eastern end of Long 

 Island, selected our asparagus field as 

 her home. The bird does not make a 

 nest, but lays her four eggs anywhere 

 on open ground in the sunlight. The 

 size of the eggs is wonderful. The bird 

 in body is smaller than our robin, but 

 her eggs are three times the size of the 

 robin's. I am sorry we did not take a 

 photograph when the bird was near the 

 eggs. As we had to cultivate the field, 

 it being a young peach orchard, the 

 trees eighteen inches high, the birds be- 

 came used to us although they did not 

 cover the eggs in the middle of the day, 

 if the weather was clear. I think two 

 weeks were spent in hatching, but I am 

 not certain. The result was a bill, two 

 legs and a ball of down. The yoving 

 birds could fly in two weeks. What 

 the old birds did for me without pay, 

 if I put a pecuniary value on their 

 labors, would have been worth about 

 twenty dollars. They kept an acre of 

 asparagus clear of the asparagus 

 beetle for the season, by eating them 

 all, with how many other bugs I do not 

 know. They now have a lease of the 

 place for as many years as they will 

 take it. The young birds have left for 

 the South ; the older ones will go in a 

 few days. Why the young go first with 

 other young birds I do not know, but 

 as I have gunned on the eastern end of 

 Long Island for years, I do know that 

 the young flight comes first, and as a 

 rule on August first. The flight of the 

 old begins about two weeks later and 

 lasts till the first of September. I have 

 shot many ring-necked snipe, calling 

 them to stool by a penny whistle, and 

 have thus destroyed many cheap labor- 

 ers that would have helped the farmer. 



Yours truly, 



Robert L. Case. 



