86 DRAGON FLIES VS. MOSQUITOES. 



the experiments herein described show, it is impossible to 

 fulfill, in respect to dragon flies, many of the conditions 

 essential to rearing, viz., pairing and fertilization and de- 

 position of ova. It is generally easy to carry an insect 

 through the larval and pupal stages and obtain the imago 

 or perfect insect, but this is not breeding ; and while the 

 larvpe of dragon flies may be captured and carried through 

 the larval and semipupal stages in limited numbers (a 

 portion will certainly die), this is not rearing, in the sense 

 in which fish or silk worms are bred. A negative reply, 

 therefore, to Mr. Lamborn's proposition could be made at 

 this point, provided the experiments above described in 

 the direction of rearing dragon flies were accepted as ex- 

 haustive and conclusive ; and it is to meet that exigency 

 that so many apparently disconnected details relating to 

 the life history of each of the insects above named have 

 been narrated. Irrespective, then, of the question of rear- 

 ing, we may ask, what chance has an insect producing a 

 single brood in a year, or even longer, highly sensitive to 

 every change of temperature, and whose actual existence 

 in the imago is confined to a few days, to destroy one to 

 whom every year adds a long line of generations, whose 

 egg producing capacity is reckoned by the thousands, and 

 to whom only the severest weather has any terrors ? How 

 can an insect handicapped as above stated, whose early 

 stages must be confined to an element in restricted po- 

 sitions, such as rivers, ponds, ditches, and marshes, where 

 the water is constant for a considerable period, compete 

 in numbers with or annihilate the mosquito, a habitant of 

 the same element, to whom not only such waters, but 

 every transient puddle, clay pit, pool, hollow stump, or 

 rocky depression affords a "coign of vantage" to rear 



