44 



OUTLINES OF ENTOMOLOGY. 



yielding aphids are great favorites with the ants, which take various 

 measures for their protection, even when they cannot transport them 

 to their nests. 



The great majority of our ants belong in the genus Formica. These 

 have no sting, but will sometimes bite severely if they have access to 

 the tender skin. They have but one node between the pedicel and ab- 

 domen. Our largest species is Formica 

 pennsylvanica, which is black, and three-fifths 

 of an inch long. It is a wood- borer and may 

 often be found in hollow trees and decaying 

 stumps. Formica sanguinea, a medium-sized 

 red species, is the most common slave, 

 making ant. 



Ants belonging to the genus Myrmica 

 are mostly small, bright-colored species, 

 with two nodes or scales between the abdo- 

 men proper and the thorax. One of the 

 species, Myrmica molesta, Say, is the small 

 "red ant," often so troublesome to house- 

 Red Ant (Myrmica), greatly enlarged, keepers. 



CHAPTER XII. 

 Order HYMENOPTERA . Section TEREBRANTIA. 



PARASITES AND GALL-FLIES. 



[Fig. 19.] 



Ichneumon Fly (after Riley) . 



This division of the H YMENOPTER A includes both the species that 

 are of most service to man, and those that are most directly injurious. 

 They are grouped in the same section because in all, the ovipositor is 

 a piercer, adapted for penetrating either hard or soft substances. It is 



