nifying glass. There are three forms used by Entomologists, not speaking of 

 the compound microscope. First a simple lens, called by various names ac- 

 cording to its use, as reading glass, retouching lens, etc. Second, a glass such as 

 jewelers put over one eye. Third, a photographer's retouching hood. This 

 device consists of an aluminum hood in which two lenses are set so as to 

 form a single magnifying glass. It relieves the constant strain on the worker's 

 eyes, leaves both hands free, is inexpensive, can be procured of any dealer 

 in photo supplies. 



THE DRAGON FLY. 



By W. Hogg, B. E. N. A., 79 Albert Road, Harrogate, England. 



There is no fly which has the marked and distinctive peculiarity of a dual 

 existence as the above-named. In its larval condition it can no more exist out 

 of the water than a human being can beneath its surface, whilst in its mature 

 condition it must have air, and placing it in water would terminate its existence. 

 Perhaps it will be interesting to follow it through its varied stages. En passant, 

 we may assume that it receives its name from the voracity of its appetite, and 

 from its powerful jaws, which it possesses in both stages of its life. The largest 

 part of this is spent as an aquatic insect, and a short period in the air, but 

 whether it be terrestrial or aquatic it is equally ferocious. The eggs are de- 

 posited in the late autumn in the water, and are there hatched. It is a peculiar 

 looking insect in its embryo state, about 1 Yl inches in length when nearly full 

 grown, with an upraised tail, the whole being pale greyish brown in colour. 

 If two or more are placed in a bottle, and insect life is not at hand, the strongest 

 will turn cannibal and feed upon his weaker brethren. It may be noted here 

 that the writer has placed flies upon slow running streams, and noticed that so 

 long as the insect was quiescent, it floated slowly along, but directly it began 

 to struggle it fell a victim to a fish or a dragonfly larvae. For some time the 

 subject of our chat remains in its winter quarters, waging war on all the aquatic 

 denizens of the pool, but as the middle of summer approaches it becomes languid 

 in its movements, cares less and less for food, and at last ceases to eat altogether. 

 Meanwhile, a wonderful change has taken place in its breathing organs; it fails 

 to extract oxygen from the water, and must breathe the air or it will die. It 

 makes its way to any object projecting or growing out of the water. This it 

 slowly ascends, for its legs are stiffening, and at last it reaches a suitable height, 

 where it awaits its escape from its aquatic life. The skin rapidly dries in the 

 sun, and the insect in its struggles for breath splits it along the back, and it 

 inhales the air it has longed for. New strength comes rapidly, and the insect 

 soon withdraws its head, the legs follow and assist the rest of the body to be 

 withdrawn as from a sheath, whilst the empty shell is left clinging to the plant 

 or projection which the pupa had climbed. So complete is this that the writer 

 has seen them removed and brought home by naturalists. When thus released, 

 the dragon fly is helpless, and the wings hang limp and without beauty, but pos- 

 sessing air, at every respiration this is forced into them, so as to gradually loosen 

 the folds into which they have been packed. If the sun be warm, both pairs 

 are soon open to their full dimensions, and the dragon fly darts off in pursuit of 

 food. Its voracity is unequaled. A large butterfly is quickly disposed of, and 

 the dragon fly crunches up the body of its victim in its powerful maws, and though 

 the wings are generally discarded, a part of them will sometimes follow the body 

 into the dragon fly's insatiable stomach. The Rev. J. G. Wood, M. A., com- 

 menting on the dragon fly appetite, says: "A lion cannot compare with the 

 dragon fly in point of voracity. Suppose that any one were to assert that a 



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