THE IXSECT WORLD. 



365 



fully take out and destroy plants that have wilted down beyond 

 recovery, because in this way the maggots are destroyed or pre- 

 vented from coming to maturity. 



Other root-maggots may be treated on the lines just laid down, 

 and nothing can be gained by multiplying instances. Too little 

 is known of most of the leaf-miners to give any general directions 

 concerning the methods which may be used to check them ; but 

 one remedy, or rather preventive measure, is always useful. A 

 crop of infested leaves should always be disposed of as soon as 

 possible. For instance, if beet leaves are attacked at the time 

 the roots are harvested, they should be at once destroyed, and 

 with them the insects yet in the plants. In this way much can 

 be done to lessen their number for the ensuing season. Direct 

 applications for leaf-miners are unsatisfactory, because of the 

 difficulty of reaching them. 



The remainder of the Muscid flies differ from all the preceding 

 in that they have no perceptible winglet or alulet just below the 

 anterior wings. If the " blow- fly" or the ''house-fly" be exam- 

 ined, it will be found that just behind the base of the large wings 

 there is a little flap resembUng in appearance a minute wing. 

 This is called the "winglet" or "alulet," and it is more or less 

 obvious in all the Muscids of which we have heretofore spoken. 

 It is absent in all the other groups, and serves to divide this 

 large family into two fairly distinct series. 



We find it absent in a large series of flies belonging to the 

 Trypetids and Ortalids, which are usually small in size, often 

 metallic in color, and with the wings frequently banded or mot- 

 tled. Some of the species have the habit of strutting up and 

 down with the wings elevated and spread out, and this has given 

 them the name "peacock flies." They are gracefully built in 

 most instances, and are noticeable by keeping the wings in con- 

 stant motion even when feeding or walking about on flowers, 

 where they are most frequently found. They fly rather slowly, 

 and, as a rule, are easily captured. The abdomen of the female 

 frequently ends in an extensile, horny-tipped ovipositor, by 

 means of which the eggs are laid in the plant tissue in which the 

 larvae feed. Most of the members of the series feed in plant 

 tissue of some kind, either in leaves, in stems, or in fruits, and a 

 number of them are gall-makers. The most notable instance of 



