BULLETIN 198. 



THE GRAPE LEAP- HOPPER. 



193 



quiet for some time. For a few days before the eggs hatch there is a 

 conspicuous dark spot at one end of the egg, which represents the 

 eye of the developing nymph within. It is at this end that the egg 

 covering is broken and the nymph makes its way out. 



First Stage. The young nymph upon hatching from the egg is a 

 very small semi-transparent whitish creature with conspicuous red eyes. 

 The wing pads are invisible. The head and thorax appear large in 

 proportion to the abdomen, and the insect walks in a more or less 

 wabbling manner. The length of the period from hatching to the 

 first molt is four days. 



Second $ta(/e. After the first molt the conspicuous red pigment in 

 the eyes is partly lost, and the form of the body becomes more cylin- 

 drical. Indications of yellow markings appear on the thorax, and the 

 wing pads just begin to appear as lateral buds. The length of this 

 stage is two days. 



Third Stage. The markings of the thorax become a little more 

 prominent, and the wing pads appear as buds extending posteriorly to 

 the caudal margin of the first segment of the abdomen. The hind 

 margin of the thorax is curved or arched, as a result of the wing pads 

 projecting posteriorly at the sides. The length of this stage is three 

 days. 



Fourth Stage. There is not much change in the general appearance, 

 except that the wing pads are now conspicuously larger and extend 

 1o the caudal border of the second abdominal segment. The length of 

 this stage is four days. 



Fifth and Last Stage. The wing pads now extend to the caudal 

 border of the third, or to the middle of the fourth, abdominal segment. 

 The length of this stage is five days. 



After the fifth molt the fully formed wings appear, extending to 

 beyond the tip of the abdomen. 



Some of the life-history work carried on to determine the number 

 and length of the nymphal stages is indicated in the following table : 



