GARDEN INSECTS. 



189 



toll of the fruit ; another section preys upon vegetables ; and yet 

 others affect flowering plants. The most destructive are amongst 

 the smallest— Tortrices, or Leaf Rollers, not one of which exceeds 

 an inch in the stretch of the wings. They are moreover the 

 most difficult to deal with, feeding as they do in the tube-like 

 retreats which they construct in such an ingenious manner, and 

 which has given rise to the appropriate name bestowed upon the 

 group. From insecticides they are fairly safe, while they do not 

 run the same chance of being detected by the insectivorous 

 birds. Two of the most destructive, taken all round, are the 

 Codlin Moth and the Plum Moth. As moths, nearly all the 

 group are short-lived, and flying as they do in early morning or 

 at dusk they are not often seen except by entomologists. 



Diptera. — Very few insects of this order, the members of 

 which are characterised by possessing only one pair of wings, 

 exert any important influence in the garden. The larvae of 

 the Craneflies (the tough Leather- jackets) and the Onion-flies 

 are perhaps the most generally known and most injurious. Of 

 late years, however, another species has been causing the apple- 

 grower some anxiety. This is Trypeta pomonella, whose cater- 

 pillars feed upon the pulp of the fruit. The perfect insects closely 

 approach the house-flies, but possess very prominent eyes of a 

 most brilliant colour. Turning to friends, there are none more 

 useful than the Hawk-flies (Syrph/us), whose lovely hues and 

 bright yellow spots are very distinct. The larvae feed upon aphides, 

 and are frequently found upon rose bushes and chrysanthemums. 

 They taper considerably towards the head, but have a blunt and 

 widish hinder extremity. Their method of progress is somewhat 

 curious, and has been aptly likened to the movement of the 

 leeches of our ditches. As soon as the grubs are full-fed they 

 attach themselves by their tails to the food-plant, using a kind of 

 sticky secretion for the purpose. Thus the pupal stage is passed, 

 and the perfect insects quickly emeige. Such larvae as are found 

 should never be interfered with, as they are amongst the most 

 voracious of all aphis-feeding insects. 



Hemiptera. — In this order the members are characterised by 

 possessing a beak-like mouth, consisting of four sharp stylets, by 

 means of which the juices of plants are extracted. The order 

 is again subdivided into Heteroptera and Homoptera purely on 

 the structure of the wings. So far as the gardener is concerned 



