68 



SCHOOL ENTOMOLOGY 



be descended from one of the winter eggs if all survived 

 and reproduced, would, at the end of the season be 

 beyond human comprehension. They are rivaled in fecun- 

 dity only by some of the 

 scales and by other insects, 

 notably the May-flies. 

 Aphids secrete from the 

 abdomen through the in- 

 testine, a sweet sugary 

 substance called honey- 

 dew. This honey-dew is 

 a favorite food of ants and 

 any plant infested by 

 aphids will be found to be 

 frequented by ants which 

 are at times accused of 

 doing the damage which is 

 actually caused by the 

 plant-lice. The ants do 

 sometimes injure us indi- 

 rectly on account of their 

 fondness for the honey- 

 dew. One species, for example, cares for the eggs of the 

 corn-root aphis during the winter and in the spring places 

 them on the roots of suitable food plants. Many re- 

 markable and often fanciful tales are told of the care 

 exercised by ants over their little green " cattle" as some 

 people are pleased to term the aphids. 



For further discussion of some species and the reme- 

 dies used, see pages 295, 302, Part II. 



FIG. 45. Gall Formed by Plant Lice 

 (Pemphigus sp.), on Leaf Stem 

 of Cottonwood. 



