CLASS insecta: order hemiptera. 



321 



Fig. SIS. 



deposited on the plants in the ax;tumn hatch in the 

 spriag asexual and wingless individuals. These produce 

 living young, likewise asexual, in succession, often to 

 the twelfth generation. At the close of summer, winged 

 and sexual ones appear. These pairing, 

 their eggs do not hatch until the following . 

 spring. This method of propagation is 

 called Parthenogenesis. It has been calcu- 

 lated that a single Aphis will produce a 

 billion young in a summer. One species bobc Loa^.^a^^ifled. 

 {Eriosbma lanigera), covered with a woolly, 

 flocculent substance, causes the apple-blight by stinging the 

 bark, when the leaves turn yellow and drop off. 



Mg. S79. 



Acry(Rum aleutaclum, Leather-colored Locust (upper figure). 

 OyrtophyUm concoAms, Katydid (lower figure). 



while gorging themselves with the honey extracted froip the tender hark, and 

 oheerve the treatment they receive from the ants, which keep them, as we do cows, 

 extracting from them a sweet liquid of which they are very fond. 



