58o 



Marvels of the Universe 



fhnlo hu] Uliial' J/ni'i, l>.,<c., f'.tJ.S. 



THE GRUB OF THE LACE-WING FLY. 



It is provided ^vith two pairs of long, sharp! j 

 pointed, sickle-shaped jaws, each pair fitting togethe 

 to form a hollow tube. N^ ith these jaws the grub ha 

 here seized its prey Ian Aphis' and is sucking th 

 juices out of its victim's body. 



Photo 



by} 









Uliiiih .Vnin, B. 



Sc., F.E. 



N. 



THE GRUB 



OF 



THE 



LACE-WING 



FLY 





As 



soon 



1 as it 



has 



emer 



ged from the egg it will 



attack 



and 



devour 



any 



unh 



atched egg or 



emergi 



ng 



grub w 



ithin 



reach. 













leaf, each is suspended at the end of a long slender 

 stalk ; in some species all the stalks of a group of 

 eggs are united in a common bundle, though more 

 often each egg remains quite distinct. It is interest- 

 ing to note that these little groups of stalked eggs 

 were classed b\' some of the older naturalists as 

 mosses ! 



When first laid, the eggs are green in colour, but 

 gradually change, until just before hatching they are 

 white with the exception of two little brown spots 

 at one end ; these are the eyes of the enclosed larva 

 showing through the shell. The little pearly-white 

 larvEe appear after about a week, and are at once 

 very voracious. Each wall remain for a while on its 

 own empt\- egg-shell and attack and devour any 

 unhatched egg or emerging larva within reach ; so 

 that in the cases where the eggs are all united in a 

 bunch, it is only the first larva or the first few that 

 stand a chance of survival. Throughout life, in fact, 

 the larvse are very liable to become cannibals if the 

 least excuse of shortage of aphides be afforded them ; 

 though if these are plentiful they may be kept to- 

 gether with a fair amount of safety. The larva is 

 provided with two pairs of long, sharply-pointed, 

 sickle-shaped jaws, of which the corresponding 

 members of each pair fit together in such a manner 

 as to form a hollow tube between thsm leading from 

 the tip into the mouth. When it seizes the prey the 

 lar\-a merely nips it between the points and sucks 

 up its juices into the mouth without chewing the 

 body in any wav. As soon as the aphis is sucked 

 dry, the larva tosses away the corpse, at once spears 

 another green fly, treats it in a similar summary 

 fashion, and so on with one after another in rapid 

 succession, soon causing havoc in the colony that it 

 has attacked. 



Another kind of Lace-wing ¥i\, instead of dis- 

 carding the empty skins of its victims, carries them 

 about on its back, so that it is soon completely con- 

 cealed under a heap of debris, and until it moves is 

 passed over as a mere lump of dirt in the middle of 

 a leaf. In this case the main object of the con- 

 cealment is, no doubt, to protect the larva from the 

 attacks of insect-eating birds ; that it should enable 

 the creature to approach its prey unobserved is here 

 of little importance, since aphides are probably too 

 sluggish to move whether the\' perceive the foe or 

 not, though it may be noted that the species which 

 practise this mode of concealment are found more 



