106 



KNOWLEDGE. 



[May]1,'1897. 



wings quietly (and what a charm there is in this mysterious 

 quietness !) expand, and the legs are brushed one over the 

 other until freed from every particle of the delicate pellicle, 



Fig. 1. — Empty Pupa Case and Wasp Fly [Si/rp/uis). 



and they are fit to comb the antenna' and arrange every 

 sensory hair in its right place. Lastly the wings are deli- 

 cately brushed down until the entranced observer almost 

 fancies he can see the soft blush of colour stealing over 

 the membrane ; then a sudden movement of the antennae 

 denotes that the work is done, and as the creature walks 

 along in its virgin beauty the light playa on its wings in 

 an endless variety of tints. 



Countless numbers oiAphidx never reach maturity, owing 

 to the relentless attacks of the larv.i' of the common ladybird 

 beetle, which is, without doubt, one of the most beneficial 

 of all insects ; though at one lime, not very far distant, 

 it was looked upon as a blight ! But now, even some of 

 the British farmers regard it as their friend. The larva 

 works a great deal completely out of sight, hidden away in 

 the distorted leaves of the apple tree suffering from "the 

 blight," where, surrounded by these bloated creatures, the 



Via. 2. — Willow Saw-Fly {yematu.i qallirola). 



busy ladybird lays a patch of sugarloaf-shaped, yellow 

 eggs, from which the sooty-coloured larvre soon emerge to 

 commence their work of extermination. In ten or twelve 



days they are full fed, and attach themselves by the tails 

 to the leaves, and change to a shrivelled-looking chrysalis. 

 Sometimes more than a dozen of them may be found in a 

 single curled-up leaf. 



Another most useful larva is that of the lovely golden- 

 eyed, lace-wing fly C/Vci/sn/x/, which, with its long and 

 curved jaws, makes short work of every " green fly " 

 with which it comes into contact. The perfect fly con- 

 tinues the work of destruction ; but it is as well not to 

 handle this lovely lace-wing fly, as it has a habit of giving 

 out the most abominable odour — no doubt as a means of 

 defence. The delicate green eggs, fixed at the ends of 

 silken threads, are 

 objects of great 

 beauty and interest. 

 Seated on a leaf, the 

 lace-wing aflixes from 

 the tip of her abdomen 

 a small pad of "silk" ; 

 then, drawing her 

 body away from the 

 leaf or stalk, she 

 stretches a short 

 thread, the oval egg 

 being laid>t the end. 

 The abdomen is again 

 brought down on to 

 the leaf, a fresh 

 foundation made, the 

 silk drawn out to the 

 same distance, and 

 another egg laid at 



the end. This operation is continued until a dozen or 

 more stalked eggs are laid ; but, in spite of this wonderful 

 protection, they sometimes fall a prey to a prowling earwig. 

 I have not yet bred any parasite from these eggs, though 

 I expect to do so. 



Of all the beneficial larvrB to be found in a garden, 

 not one can compare in importance to those of the various 

 kinds of wasp flies ; and yet how few gardeners know this 

 larva, the rose grower's greatest friend. 



Observers of msect Ufe know that this wasp or hoverer 

 fly is in the habit of depositing an egg or two on leaves and 

 stems where the Aphhhe are feeding and breedmg. These 

 oval eggs are pure white, about a fiftieth of an inch long. 

 Some of the shells are embossed all over with delicate 



Fig. 3. — Saws of Nematus f/allicola. 



Fig. 4. — Section througli Willow Gall, with Larva of Savv-Flv. 



markings, while others are studded with minute projec- 

 tions not unlike silver nails, with exquisitely chased heads — 

 grand objects when seen in the microscope with an inch 

 objective. In three or four days, from each egg is hatched 

 a tiny maggot-shaped larva, which even before it has fully 

 escaped from the shell commences to wave its little body 

 about, not unfrequently touching an aphis, which it 



