APHIDES, OR 



plant by freezing temperature is nearly impossible in 

 any of our Southern States." 



Mr. J. L. Normand, of Marksville, Louisiana, 

 finds that the tree will endure a zero temperature. 

 It is coming to be considerably used as a stock for 

 oranges, particularly for the Satsuma or Oonshiu. 



PLANT LICE. 271 



A fruiting branch is shown in the cut on this page. 



The Satsuma or Oonshiu orange is undoubtedly 

 one of the most valuable of the recent acquisitions 

 to our Southern horticulture. The illustration of a 

 pot-grown tree on page 269 will be interesting to 

 amateurs in the north who wish to grow curiosities. 



APHIDES, OR PLANT LICE. 



Few plants except those of the lowest orders are 

 exempt from the ravages of aphides or plant lice, 

 though some are injured much more than others. 

 Some species of 

 aphis c o n ii n e 

 their attention to 

 particular spe- 

 cies of plants ; 

 others attack sev- 

 eral species. 

 Thus the poppy 

 aphis and that 

 which feeds usu- 

 ally on the pink 

 are also found on 

 asparagus. 



Aphides in gen- 

 eral are wingless, 

 but in the autumn 

 winged specimens 

 of both sexes ap- 

 pear. The eggs are 

 laid in the crevices 

 of bark and simi- 

 larly sheltered 

 spots. The insects 

 hatched from the 

 eggs shed their 

 skin several times, 

 but remain wing- 

 less. They are all 

 female, and multi- 

 ply asexually when 

 from four to ten 

 days old. A single 

 aphis produces 

 about go young, 

 and it is stated 

 that 5 generations 

 have been pro- 

 duced between 

 July i2th and Au- 

 gust igth. The fifth generation, if none perished be- 

 fore reproduction, would amount to 6,000,000,000. An- 

 other observer has stated that at least 10 generations 

 are produced in warm, moist seasons. The eggs laid by 

 the later generations in early autumn hatch in a few 



A Fruiting Br.^nch of the Satsuma Orange 



days, producing winged females and a comparatively 

 small number of males. These reproduce sexually, and 

 the eggs are laid in sheltered positions as before men- 

 tioned. The col- 

 or of aphides va- 

 ries with that of 

 the plant on which 

 they live. The 

 apple aphis, A. 

 niali^xs light green; 

 the plum aphis, A. 

 piniii, green or 

 bluish-green, cov- 

 ered with a whitish 

 dust ; the rose, A. 

 >'osic, is dark green. 

 Those feeding on 

 the elder, the 

 cherry and the 

 bean are blackish ; 

 those found on the 

 linden are yellow, 

 and the cabbage 

 and white thorn 

 aphides are whit- 

 ish-gray. On the 

 back of most spe- 

 cies are two hollow 

 prominences, the 

 so-called "honey 

 tubes, " from which 

 exudes a sweet 

 liquid much sought 

 by ants. The lat- 

 ter, by stroking the 

 aphides, increase 

 the flow of this 

 liquid, and arethen 

 commonly said to 

 be ' ' milking their 

 cows." The idea 

 that ants destroy 

 aphides is erron- 

 eous, however. 

 The aphis feeds by choice on the youngest and soft- 

 est parts of plants, extracting their juices by means of 

 its long proboscis. The part of the juice not digested 

 exudes from the honey tubes. As the insects are chiefly 

 found on the under side of leaves, the sweet liquid falls 



