158 INSECTS AFFECTING THE ORANGE. 



Tne development of this sou them Aphis differs from that of its north 

 ern congeners, in' that the winged and the wingless individuals occur 

 together at all seasons, and both forms produce their young living. The 

 males remain undiscovered, and it is entirely possible that they rarely 

 make their appearance, perhaps only at intervals of several years. In 

 the warm climate of Florida the cold is never sufficiently severe to 

 kill winged females, and the Orange not being deciduous a supply of 

 food is nearly always at hand. A winter egg is not, therefore, a neces- 

 sity, as in the North, and it may be that none are deposited in ordi- 

 nary seasons. The late fall broods consist in great part of the winged 

 females, while in spring, and especially in midsummer, the wingless form 

 predominates. 



In the act of birth, the hinder end of the young Aphis appears first. 

 The young is slowly protruded from the body of the mother, until only 

 the tip of the head remains unexpelled. During the process aud for 

 a few minutes after, all motion outwards ceases, the larva remains im- 

 movable and with its members rigidly applied to its body. Soon it dis- 

 engages first one leg, and then another, until all are Widely extended. 

 The antennas are then raised and brought forward. This movement 

 severs the contact with the mother, and the new-born young drops upon 

 its feet, in the full possession of its faculties (which it makes no delay 

 in putting to the test). Within ten minutes from the time when its ex- 

 pulsion from the mother began, it is quietly feeding by h^r side, its 

 sucking beak inserted in the tender tissues of the leaf, and its body 

 rapidly becoming distended with the juices of the plant. In less than a 

 week after its birth, the plant-louse has become adult, and begins in its 

 turn to produce young. 



Destructive powers. The Orange Aphis attacks the tender new growth ; 

 it checks the growth of young shoots, and curls the tender leaves. 

 With such a direct and rapid method of reproduction, and with a winged 

 form of female ever present to spread the pest, it will be seen that this 

 insect presents a truly formidable aspect as a destroyer. Were it not 

 held in check by numerous enemies and parasites, it would soon ruin 

 the trees by destroying the new growth, and render the culture of the 

 orange for profit an impossibility. 



The work of enemies. Such, however, is the activity of its enemies 

 that not a single individual Aphis escapes destruction, or is allowed to 

 exert to the full its reproductive powers. Colonies rarely attain great 

 size, and, in fact, are frequently exterminated in their very beginning, 

 and before any appreciable injury has been done. 



The parasite. The principal agent in accomplishing this result is a 

 parasite, whose larva, feeding internally upon the Plant-louse, finally 

 kills it. In dying the body of the Aphis becomes distended to the 

 utmost, assumes a globular shape, and turns to a dingy yellow color. 

 In drying it adheres firmly to the plant. (Plate XIII, Fig. 3, c.} 



Within the body-cavity of its victim, the space within which it nearly 



