228 



Marvels of Insect Life. 



Winged Green-Fly. 



Green-fly that develop wings are usually males, or imperfect females, that 

 have been produced for colonizing purposes. The production of a winged 

 generation takes place as a rule when the juices of the original food-plant are 

 less abundant. 



Several of the smaller insectivorous birds 

 onslaught, small ichneumon- wasps lay their eggs in them, 

 and certain bugs go about spearing them with their sucking 

 needles. 



These unprotected minute creatures, that so trouble 

 the gardener, are really among the most remarkable of 

 living things, and though they have been the study of all 

 great naturalists of the eighteenth and nineteenth centuries, 

 we are far from having a complete and satisfactory account 

 of them and the phenomena of their development. In our 

 own day Buckton has devoted four volumes to a description 

 of the British species alone, and something more has been 

 learned since these volumes were published. It will be seen 

 that in a brief account one cannot go into detail. 



Throughout the spring and summer the observer will 

 have noticed that the crowds of green-fly that abound on 

 nearly all plants in his garden are wingless ; and with the 

 knowledge of the course of development that prevails 

 almost throughout the Insect-world, he would be justified 

 in assuming that these will in the course of a few days 

 develop wings, for he is quite familiar with them in the 

 winged condition. But it is rarely that these summer broods 

 produce winged individuals. In order to do their work of 

 checking somewhat the redundant growth of plants and sup- 

 plying food for numerous creatures, the ordinary slow pro- 

 cess of passing through successive stages before attaining 

 reproductive powers is not sufficient. Eggs that were laid 

 in autumn, and have been remaining dormant during the 



1 Coccinolla. - Syrphus. 



this fluid makes the attacked 

 leaves curl, become spotted with 

 brown, and in bad cases shrivel 

 up ; sickly shoots under the attack 

 wither and are shortened. It is 

 one of Nature's methods of prun- 

 ing. When things are getting 

 desperately bad a summer storm^ 

 comes on, and the green-fly that 

 defied the gardener's attacks are 

 all but cleared off. Or, failing the 

 storm, a host of lady-birds ^ or 

 hover-flies- appear and lay their 

 eggs close at hand. The eggs 

 quickly hatch, and the grubs at 

 once set to, attacking the green- 

 fly' like a wolf in a sheep-fold, 

 join in the 



Phot, I by] [H. Biistin. 



Green-Fly on Rose-bud. 

 .\ colony of wingless green-fly has 

 begini to cover a rose-bud in a way 

 that is painfully familiar to the ex- 

 asperated though patient gardener. 

 Jiach one has a sucking beak plunged 

 deeply into the tissues of the rose, 

 from which it is sucking the juices 

 that should nourish the flower, 

 .^bove are some cast skins thrown 

 off in the process of growth. 



