Half-winged Insects 



729 





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The True Fkog-hoppers are small insects about a quarter of 

 an inch long, found among grass and bushes. The fore wuigs are 

 of rather a stout consistency and uniform in colour (often yellowish), 

 and the hind wings transparent. The larvte are soft grubs, and 

 lire in the masses of froth so common in grass and bushes, which are 

 vulgarly known as " cuckoo-spit.'' 



Passing over several families of small species, we arrive at two 

 which contain many very destructive insects. The Aphides, Plant- 

 lice, or Smother-flies are the small green or brown winged or 

 wingless insects which frequently cover the shoots of roses and 

 other trees and plants, and exude a sweet sticky substance, called 

 "honey-dew," very attractive to ants. One species, known as the 

 American Blight, is extremely destructive to apple-trees, patches 

 of a substance resembling white cotton appearing on the bark. 

 Under these patches the bark rots from the attacks of the insects, 

 the pest being very difficult to eradicate. 



Many of the Aphides exhibit the curious phenomenon known 

 as " alternation of generations." The first 

 brood consists of winged males and females ; 

 but the eggs which the latter lay produce 

 exclusively wingless females, or rather sexless 

 creatures capable of laying eggs, and these 

 multiply indefinitely for a time, till perfect 

 males and females are again reproduced. In 

 some cases the winged forms live on the 

 leaves of trees, and the wingless forms at 

 the roots of grass, etc. One of the most 

 destructive of all these insects is the Yine- 

 APHIS, which was probably introduced into 

 Europe from America, and which threatened 

 at one time almost to destroy the vine in- 

 dustry in France. Wingless sexless forms 

 live and multiply at the roots of vines ; and 

 in summer winged males and females are 

 produced, which fly up, and lay eggs on tlie 

 leaves ; while some of the wingless insects 

 also quit the ground, and form small galls on the vine-leaves. 

 Although very abundant in America, the insect is not nearly so 

 destructive to the plants which it attacks as in Europe. 



Some species of Scale-insects are almost equally destructive, 

 especially to greenhouse plants. The male is slender and two- 

 winged, but the female is wingless and often legless, and after de- 

 positing her eggs usually dies above them, thus forming a covering 

 to protect them from injury. Cochineal consists of the bodies of a 

 species of scale-insect which infests the leaves of a cactus in Mexico. 

 The True Lice are found on various species of mammals, 

 and imbibe their food through a proboscis. The Bird-lice, or 

 Biting-lice, form a well-defined group by themselves. They are 

 sometimes regarded as forming distinct orders of insects; but 

 some authors treat the first group as a degraded family of msects 

 allied to the Frog-hoppers, and the second group as an equally 

 degraded and aberrant family allied to the Lace-winged Insects. 



Photo hij W. P. Dando, F.Z.ti 



. Regent's Park. 



APHIS. 



A sexual wingless form. 



Photo by W.P Dando. f.Z.S.,R,:ifa,t s I'ai 



SCALE-IXSECT. 



'Jljii females die, coverinif their eg 



\\ ith their own bodies. 



w 



I'koio by IP'. P. Dando. F.Z S.,Rescnt's Park. 



SCALE -INSECTS. 



Showing their appearance when 

 crowded together ou ^ branuh. 



92 



