578 



Marvels of the Universe 



(some of which develop remarkable 

 spurs on the wrist of the wing). Never- 

 theless, the common African J3.qa.na. is 

 a prett}- creature, with its plumage of 

 rich chestnut-brown, black quills, and 

 black top to the head and neck, and a 

 face, throat and chest of pale golden- 

 yellow, while the beak and the frontal 

 shield, the big legs and feet are a pale 

 leaden-blue. 



THE LACE-WING FLY 



BY K. G. BLAIR, B.SC. 



While among the countless hosts of 

 the insect world most of the species 

 are of no economic importance to 

 mankind, yet there are, of course, vast 

 numbers that do him considerable in- 

 jury ; and in attempting to extermi- 

 nate these, or, at any rate, to keep 

 them in check, large sums of money 

 and an immense amount of labour are 

 annually expended. One of the most 

 successful methods of keeping down 

 the numbers of one of these undesirable 

 kinds of insects is to find out its natural 

 enemies, and by using all possible means 

 of favouring these and encouraging their 

 multiplication to increase the efftcacj'' 

 of their work as a scourge upon the 

 pest. 

 One very common insect pest, which, though not perhaps of great commercial importance, is 

 yet a source of constant annoyance to gardeners, amateur and otherwise, is the green fly, aphis and 

 its allies. Yet this little insect has a great number of enemies, especially amongst other insects, 

 and by finding out these and what are their habits a great deal can be done to keep down the 

 numbers of the aphis. One of these natural enemies that has already been treated of in these pages 

 is the hover fly, another is the lady-bird, while vet another is the Lace-wing Fly. The latter 

 is a rather large insect, the common species measuring about an inch and a half across the expanded 

 wings. Its body is of a vivid green with some golden markings, and the eyes are rather large, 

 prominent and of a brilliant golden colour. It has two pairs of large gauzy wings, each of which 

 shows a delicate net-Uke tracery of veins, the feature from which the fly derives its common 

 name. It frequents gardens, bushes, or rank vegetation — anywhere, in fact, where the green fly 

 abounds ; but it usually remains hidden away during the day and only flies for a short period 

 about dusk. It is then easily captured, as its flight is slow and heavy, as though the expanse of 

 wing were too great to be under the complete control of the slender body. 



The Lace-wing Fly is to be found throughout July and August. The eggs are laid on the undersides 

 of leaves, cometimes singly, but usually in groups. Instead of being laid directly on the surface of the 



IHE .AH<li^A\ JAeANA. 

 This is the larger of the two lacanas. or Leaf-walUers. found in Africa, 

 and is also the commonest, ranging right across Tropical Africa fron^ west 

 to east. It is about the size of a small plover, and has blunt spurs on the 

 \vrist of the wing. 



