582 Report of Entomologists of the 



Injury to Trees and Fruit. 



As will be shown hereafter, the scales suck the sap from the 

 trees .both from the bark and leaves. In this way the trees are un- 

 doubtedly injured to a greater or less degree according to the num- 

 ber of scales present. In one respect, however, the most serious 

 injury is done to the fruit. The scales do not attack the fruit but 

 they secrete a clear, sweet, sticky liquid known as honey dew. The 

 brandies, leaves and fruit of the trees soon*beeome partially coated 

 with this honey dew. Yery soon a black fungus begins to grow on 

 all parts of the tree and fruit where the honey dew has fallen, nntil 

 a badly infested tree will look as if it had been smoked from the top 

 to the ground. The fruit thus becomes greatly disfigured, and as 

 the fungus will neither rub nor wash off, may readily render the 

 fruit unmarketable. 



Sicliy trees are undoubtedly most readily attacked by the scales. 

 This is probably common in other cases of insect attacks upon trees 

 or other plants. The question why this is so is not easily answered. 

 Prof. Comstock, in the United States Agricultural Report for 1880, 

 page 285, suggests that the sap of sickly trees may be more nourishing 

 to the scales than that of healthy trees, for, as he also states, the scales 

 do not usually have an opportunity to select their food plant and 

 the scales certainly grow ^dgorously and quickly cover the weak and 

 sickly tree. 



Life-History, Habits and Description. 



Transformations . — With the exception of one order, individual 

 insects are said to undergo one of two forms of metamorphosis in 

 reaching maturity, namely, complete and incomplete. In the 

 former case the different stages are distinct and easily recognized 

 one from the other. An illustration of this, as commonly given, 

 may be found in the life-history of any butterfly. The butterfly's 

 egg produces a caterpillar, the caterpillar changes to a chrysalis, and 

 the chrysalis produces a butterfly. All of these stages are distinct 

 and well defined ; no one of them resembles another. This is 

 called complete metamorphosis. In the latter case, however, the 

 different stages are not so easily distinguished ; as for instance, a 

 young squash bug or locust resembles the parent in general appear- 

 ance and continues to do so more and more until finally mature. 



