182 ELEMENTARY STUDIES IN INSECT LIFE 



group, then, is sometimes called the long-horned grass- 

 hoppers. Grasshoppers proper have antennas shorter 

 than the body. 



Grasshoppers. 1 Grasshoppers are among our most 

 common insects. The life history of one of the spe- 

 cies has already been given. (Page 3.) Those living 

 in this country can be separated into three groups, 

 depending upon the structure of the adult. One 

 group embraces all those without extended ridge on 

 longitudinal median line of pronotum, and bearing 

 tubercle on center of prosternum (Acridiince). The 

 yellow grasshopper (Melanoplus differentialis} is an ex- 

 ample. The second is without prosternal spine, and has 

 an extended ridge upon the pronotum (Oedipodince}. 

 The '" dusty hoppers," so common in the roadways, be- 

 long to this group. The third are not so generally 

 known, but are easily recognized by the backward and 

 downward receding front of the head (Tryxalince}. 



THYSANOPTERA. 



These insects have four long, narrow, membranous 

 unfolded wings, well fringed with hairs, from which 

 the name of the order is taken. There are few veins. 

 The wings at rest lie horizontally along the back. 

 The mouth-parts are imperfectly fitted for sucking, 

 being intermediate in form between those of the Orthop- 

 tera and those of the Hemiptera. The metamorphosis 

 is incomplete. 



The name of the order arises from Ovaavos, thysanos, 

 fringe, and Trre/oo'y, pteron, a wing. These minute in- 

 sects are to be found under the bark of trees, in the 



'Family, Acrididce. 



