102 APPLE. FRurT APPLE THRIPS; 



and horny, with numerous impressed transverse lines, and change? 1 

 to a dull yellow or a black color, and those species which have 

 two horns forward of the tip still retain them. Within this shell 

 the insect puts on its pupa form, from which the fly subsequent- 

 ly hatches. 



The aphis, likewise, has foes within as well as without. In 

 addition to the several insects of which we have now treated, all 

 of which attack it externally, it has internal enemies also, a group 

 of insects which dwell in the interior of its body during their 

 larva state, and eventually kill it. These are nearly as efficient 

 in keeping its numbers reduced as any of those which we have 

 been considering. We will speak more particularly of them in 

 connection with the aphis which infests the cherry. 



A succession of the several species of these different kinds of 

 destroyers are making their appearance the whole season through, 

 and as many of these species are among our most common insects, 

 it will at once be perceived that thsy render us most important 

 services in destroying these pests of vegetation, and preventing 

 them from becoming excessively multiplied notwithstanding their 

 unparalleled fecundity. But without actually observing them at 

 their accustomed work no one can fully appreciate their value 

 to us, and the amount of herbage which they save from destruc- 

 tion. Wherever plant-lice become numerous, there these several 

 kinds of enemies speedily congregate and rapidly multiply, de- 

 vouring incredible numbers of these vermin, and often in a sur- 

 prisingly short space of time completely exterminating, them. 



AFFECTING THE FRUIT. 



In a round cavity ate near the tip end of the young fruit'; a minute, very 

 slender blackish-purple insect, with narrow silvery-white wings upon 

 its back resembling a long Y-shaped mark. 



The! Apple Theips. Phlceothrips Mali. 

 Although a profusion of flowers in the spring is often hailed as 

 a harbinger of a copious yield of fruit, this expectation is very 

 frequently disappointed. Whilst they are yet young, quantities of 



