PLANT-EATING INSECTS AND MYRIAPODS 217 



adult, as exemplified by such insects as moths and two -winged 

 flies. A large number of species feed on the juices of plants, and 

 inject salivary fluid into the punctures they make, often, it would 

 appear, with injurious result. Among the most attractive of these 

 are the comparatively large Cicadas (see vol. i, p. 152), the males 

 of which have earned a sort of doubtful fame from the fact that 

 they are the noisest members of the Insect class. The larvae are 

 more unlike the adults than is usually the case in the order. 

 Perhaps the most remarkable species, on account of the unique 

 length of time taken by it in passing through its life-history, is 

 the Seventeen-year Cicada (Cicada septemdecini) of the United 

 States. Most of the seventeen years is spent underground in the 

 larval stage, during which the food consists of the juices of roots, 

 according to many entomologists. 



Another good example of plant-sucking Bugs is afforded by 

 the Plant-Lice or Aphides (see vol. i, p. 353), commonly called 

 "green-fly". These minute, delicate insects often propagate at 

 a surprising rate, and damage many kinds of plants. One of the 

 most notorious forms is the Vine-Aphis {Phylloxera vastatrix), a 

 North American insect, which, introduced into Europe, has done 

 a vast amount of damage in vineyards. Its life-history is very 

 complex, and includes certain stages which injure vine-roots, and 

 others which produce galls on the leaves of the same plant. 



A rather curious family of bugs is that of the Frog-hoppers 

 {CercopidcB), including small insects with marked leaping powers. 

 The commonest British species is Philcenus spumarius, the young 

 of which are surrounded by a mass of frothy fluid, which has been 

 secreted in the intestine. This is the origin of the familiar "cuckoo 

 spits", which are common country objects. 



SPIDER-LIKE ANIMALS (Arachnida) 



The second air-breathing class of Arthropods, that of the 

 Arachnida (Scorpions, Spiders, Mites, &c.), includes animals 

 of which the large majority are carnivorous. A number of the 

 minute creatures known as Mites are, however, vegetarian in 

 habit. Some of these subsist on dead organic matter, as, for 

 example, the Meal-Mite {Tyroglyphus farince), and in this case 

 the chelicerae, corresponding to the little nippers of the Scorpion 

 (see p. 125), are, as in that case, pincer-like. The same append- 



