124 



ELEMENTARY ENTOMOLOGY 



FIG. 169. The bittersweet tree-hopper (Enchenopa 



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



mass. (Much enlarged) 



(After Lugger) 



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- 

 bracidae) have been 

 called the ' brownie 

 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 bubalns], 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," 



FIG. 170. Mass of spit- 

 tle produced by 



of 

 hence the insects of this family per, or spittle-insect 



1 vSee Btilletin Xo. 77, Bureau of Entomology, United States Department of 

 Agriculture, for a very complete and interesting account. 



