106 NATURAL HISTORY READER. 



a general rule, insects lay eggs which are hatched, pass 

 through the state of larva and pupa, and then become per- 

 fect insects. But the plant-lice go on a very different plan. 

 A female aphis fakes her place on a branch — say of the 

 rose — plunges her beak into the tender bark, and begins to 

 suck the sap. After a short time she begins to produce 

 young aphides at an average rate of fourteen per diem. 

 These young creatures are just like their mother, only 

 less, and immediately follow her example by first sucking 

 the sap of the plant and then producing fresh young. 



3. It is in consequence of this remarkable mode of pro- 

 duction that the twigs and buds become so rapidly covered 

 with aphides, the quickly succeeding generations crawling 

 over the backs of their predecessors, so as to arrive at an 

 unoccupied spot of bark in which they can drive their 

 beaks. Thus, at the beginning of a week, say on Mon- 

 day, a rose-tree may be apparently free from aphides, or 

 have at the most six or seven of the ''blight" upon it, 

 but by Thursday the whole plant will be so thickly covered 

 with aphides that scarcely a particle of the bark can lie 

 seen, the whole being crowded with the green bodies of the 

 insect, each with its beak dug deeply into the plant, and 

 draining it of its juices. 



4. The natural foe of the aphides is the bright little 

 spotted beetle known as the lady-bug, or lady-bird. Beau- 

 tiful as are the lady-birds, it is not for their beauty alone 

 that they are valued, inasmuch as they are among the 

 greatest benefactors of civilized man, and preserve many 

 a harvest which, but for their aid, would be hopelessly 

 lost. For in their larval state they feed upon the aphides, 

 and, being exceedingly voracious, devour vast numbers of 

 these destructive insects. Few persons would suppose, on 

 looking at the coccinella larva, what was its real condition 

 of life. It looks as harmless, dull, sluggish a creature as 

 can be imagined, and much more likely to be eaten itself 



