138 AN ECONOMIC ENTOMOLOGY. 



an adult in any available shelter, — under loose bark of trees, under 

 rubbish, and, in fact, wherever there is an opportunity to hide. 

 The application of whale-oil soap early in spring, just as the buds 

 begin to swell, will generally kill the insects, which are then ready 

 to emerge from winter quarters. Good practice is to scrape all 

 the loose bark from the trees during the winter, and burn it ; 

 wash at that time with a potash or strong kerosene mixture, and 

 in spring use the whale-oil soap at the rate of one pound in one 

 gallon of water, being careful to confine the spraying to the 

 trunk and larger branches. If this is thoroughly done, it forms 

 a film over the trunk which no insect will voluntarily pierce. A 

 liberal application of whitewash is also advantageous, and should 

 be put on with a knapsack sprayer and Vermorel nozzle. 



We have many species belonging to this family, some of them 

 gall-makers on the hackberry, or Celtis ; but none others occur in 

 sufficient numbers to be of economic importance. 



The ' ' tree-hoppers' ' belong to the family Membracidce , and 

 contain many odd-looking types. The general shape has been 

 compared to a beech- nut, and the most prominent part is always 

 the thorax, which may be produced into a curved horn forward, 

 into a broad hump, into a pair of curved lateral horns, into a 

 double hump, or into a dozen other forms. The species occur 

 on trees, shrubs, vines, and indeed oft vegetation generally, 

 though rarely in great numbers. Some species excrete honey- 

 dew, some lay their eggs in white frothy masses on plants, and a 

 few are attended by ants, thus resembling the plant-lice. Only 

 a few are troublesome, and of these are the "buffalo tree- 

 hoppers," belonging to the genus Ceresa. They derive their 

 common name from the fact that the thorax is cut off square 

 anteriorly, and projects into two short, lateral, curved horns, 

 which give it a fanciful resemblance to the massive front of a 

 buffalo. The head is small and scarcely noticeable, the horns 

 not being recognized at first as really belonging to the thorax. 

 This insect causes injury by laying its eggs in slits on twigs of 

 apple- and other fruit-trees. There appears to be almost a poi- 

 soning of the plant tissue, because the wounds, though apparently 

 slight, do not readily heal over, but rather open up the year 

 following, giving rise to an abnormal swelling, weak and morbid 

 in character, unable to sustain the weight of any fruit that occurs 



