INSECTS. 497 



In a genus Ooccina (Dorthesia), several species of which 

 are found in this country, the female although apterous 

 and active in all stages is completely covered with a snow- 

 white secretion, which gives it more the appearance of a 

 little plaster-cast than any thing else. 



In another tribe, the Phytophthiria, both sexes are either 

 wingless or furnished with four distinctly veined wings. 

 The rostrum springs apparently from the breast ; the tarsi 

 are two-jointed and furnished with two claws. The most 

 familiar species of this tribe are the Aphides, Plant-lice, 

 which have ever been regarded with considerable interest 

 by the naturalist, and whose curious history is doubt- 

 less well known to every one. They are all small animals, 

 with a more or less flask-shaped body, furnished with 

 six feet, a pair of antennae, and very generally with a pair 

 of short tubes close to the extremity of the abdomen, 

 from which a clear sweet secretion exudes. Both sexes 

 are at one period winged, at another wingless ; and indi- 

 viduals of the same species are often winged and apterous 

 at different periods of the year. They all live upon plants, 

 the juices of which they suck ; and when they occur in great 

 numbers, cause considerable damage to vegetation ; a fact 

 well known to the gardener and farmer. Many plants are 

 liable to be attacked by swarms of Aphides, which cause 

 the leaves to curl up, they grow sickly, and their produce is 

 greatly reduced. One striking instance is presented in the 

 devastation caused by the Hop-fly (Aphis humuli). 



The Oicadellina or Cercopidce, of which the Aphrophora 

 bifasciata, common Frog-hopper, have the antennae placed 

 between the eyes, and the scutellum visible that is to 

 say, not covered by a process of the prothorax. The 

 eyes, never more than two in number, are sometimes 

 wanting. These little creatures are always furnished 

 with long hind legs, which enable them to perform most 

 extraordinary leaping feats. 



The best-known British species, because so very abundant 

 in gardens, is the Cuckoo-spit, Froth-fly. The names 

 Cuckoo-spit and Froth-fly both allude to the peculiar 

 habit of the insect, while in the larva state, of enveloping 

 itself in a kind of frothy secretion, somewhat resembling 

 saliva; and this^ indeed, was at one time supposed to be 



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