124 



ELEMENTARY ENTOMOLOGY 



their egg laying. The different broods have been carefully mapped, 



so that it is possible to foretell the appearance in any given locality 



where the insect occurs. 1 



Plant-hoppers. The next three families may be grouped together 



under the term "plant-hoppers," as they jump off suddenly when 



disturbed. They are 

 small insects, usually 

 not over one fourth 

 of an inch long, and 

 suck the sap from the 

 leaves and stems of 

 their food plants. The 

 tree-hoppers (Mem- 



FIG. 169. The bittersweet tree-hopper (Enchenopa / V7 \ Vi K 



binotata Say). Adult (side and back views) and egg 



mass. (Much enlarged) called the " brownie 



(After Lugger) insects," for their bi- 



zarre shapes are often 



comically grotesque. The prothorax is prolonged back over the 

 abdomen and is often produced forward or up- 

 ward into horns or crests, as shown in Fig. 169. 

 One of the most common species is the buffalo 

 tree-hopper (Ceres a bubalus\ which lays its eggs 

 in the stems of weeds and young fruit trees, 

 causing large knotty scars on the twigs. Another 

 small brown species (Enchenopa binotata} is 

 common on the bittersweet vine, the projecting 

 prothorax looking exactly like a thorn on the 

 stem. Few species of this family are sufficiently 

 numerous to do serious damage. 



Here and there on weeds, grass, and tree 

 foliage will be found a little mass of froth, within 

 which may be found a small nymph, which is 

 busily pumping the sap out of the plant, thus 

 causing the froth which was formerly supposed 

 to be voided by tree frogs and was termed " frog 

 spittle," hence the insects of this family 



FIG. 170. Mass of spit- 

 tle produced by the 

 nymph of a frog-hop- 

 per, or spittle-insect 



1 See Bulletin No. 77, Bureau of Entomology, United States Department of 

 Agriculture, for a very complete and interesting account. 



