190 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 



the first sub-order is of no consequence ; but the second forces 

 itself upon his attention by reason of the fact that it contains 

 some of the most injurious pests in the whole range of insects. 

 To it belong the destructive Aphides and the Scale insects, the 

 disgusting-looking Cuckoo Spit insect, and the little-known, so 

 far as this country is concerned, Grape Phylloxera. The 

 Aphides, or plant-lice, are undoubtedly the most remarkable of 

 the whole order, alike as regards their numbers (200 species are 

 known here), destructive propensities, the variety of food-plants 

 laid under contribution, and their exceedingly omnivorous tastes. 

 This last characteristic does not appear to be as well known to 

 the majority of amateurs as it should be, and comparatively few 

 recognise in Aphis pruni, that pest of fruit-growers (for it is not 

 only a honey-dew secreting kind, but one which feeds curled up 

 in the leaves), the insect which at another season is working 

 havoc with certain Composite like Asters and Chrysanthemums. 

 This is, however, but one example out of many. Again, the 

 enormous rate at which plant-lice increase, almost invariably 

 puzzles the average gardener, who is not alive to the fact that 

 besides males and females there are asexual individuals which 

 are viviparous. Moreover these latter for several generations 

 produce others of the same kind. Of the Woolly Aphis, or 

 American Blight, little need be said ; and so, too, of the Grape 

 Phylloxera, though the life -histories of both should prove 

 interesting to every gardener. 



Closely allied to the Aphides are the Scale insects, with 

 many of which fruit-growers at any rate are very familiar. 

 Their life-history, too, is a very remarkable one. The males are 

 two-winged (sometimes wingless) flies, but by even the closest 

 observers they are seldom seen. They are quite incapable of 

 inflicting any injury upon plants. The females, on the other 

 hand, are very destructive and fairly conspicuous — at least those 

 commonly met with in gardens. Having been fertilised, or in 

 certain cases without the intervention of the male, they deposit 

 eggs, and die. With some, the scale-like bodies which were formed 

 during their larval life, either from an exudation of the body or the 

 cast skins, serve as coverings for the eggs. Other of the Scales 

 exude cottony particles like some Aphides, and the Currant Scale 

 (Pulvinaria ribesice) is one such. These white particles are very 

 common on Black and Bed Currants in summer. 



