90 DRAGON FLIES VS. MOSQUITOES. 



The breeding of diurnals is seldom attended with suc- 

 cess, and, even under the most tempting imitations of 

 Nature, with the auxiliaries of light, heat, flowers, and 

 food plant, fertilization is rarely effected. This summer 

 I bred some hundreds of V. antiopa. Many of the in- 

 sects emerged simultaneously within a small box, but 

 not a pair mated ; and, later, the same box was similarly 

 filled with D. arcliippus, with a similar result. These 

 facts are only quoted by way of contrast in this connec- 

 tion. Of the thousands of diurnal Lepidoptera which I 

 have reared by capturing the larv?e, not one pair ever 

 mated, and artificial fertilization of the ova is out of the 

 question. The same difference exists among other orders 

 of insects. Among the Hymenoptera, bees may be 

 reared in swarms from year to year, but it is doubtful 

 whether a ''hornet" or "yellow jacket," both assiduous 

 destroyers of flies, could be ; and the very nature of the 

 Ichneumonidse and Tachina, useful as they are, forbids 

 any artificial multiplication. 



A request is made in the circular that the reply contain 

 a suggestion as to what insects may be utilized for the 

 purpose therein named. My own large local collection, 

 embracing all orders, and well represented in species, with 

 scarcely an exception the result of my personal labor, and 

 with the life history of each of which species I am measur- 

 ably familiar so far as the requirements of this paper are 

 concerned, has been carefully examined to the above end, 

 and as a result of such examination I am compelled to 

 admit that there is not a single insect, from among the 

 scores of insectivorous species, which can be recommended 

 as advisable to breed artificially — practicability, economy, 

 and convenience considered. 



