42 The University Science Bulletin. 



situations where they receive the most sunshine. Most of our 

 species occur on trees, but there are several that are found on 

 shrubs^ and some occur on weeds, grasses and clovers. 



The majority of our species of tree hoppers are found to over- 

 winter in the egg stage. This stage, therefore, occupies by far 

 the longest period in the life history of the insect. The eggs are 

 deposited for the most part in the twigs. Here they may be placed 

 in simple incisions in a row, or the well-known method of oviposi- 

 tion of Ceresa biibalus may be used where two curved iuQisions, 

 facing each other, are made. Some species also oviposit in the 

 buds, while our common Entylia concisa lays its eggs in the veins 

 of the leaf of Ambrosia trifida. Funkhouser gives the axils of the 

 leaves as the place where Telamona ampelopsidis oviposits, while 

 Thelia bimaculata lays most of its eggs in the roots or on the stem 

 below the surface of the soil. 



While most of our treehoppers hibernate in the egg stage, Funk- 

 houser states that Entylia bactriana and Publilia concava over- 

 winter as adults. The writer has taken Entylia concisa late in the 

 fall in the rubbish and grass around its host plant. In fact, on 

 September 8 he has found the eggs of this species just hatching, 

 while on September 11 he has taken all the nymphal instars and 

 newly matured adults on a single leaf. 



The number of generations in a season is usually one, by far the 

 larger number of our species having a single annual brood. Some 

 species, however, have two broods and some probably three, while 

 Vanduzea arquata is said by Funkhouser to have as many as four 

 generations. The same is seemingly true of our Vanduzea trigut- 

 tata. 



The usual life history of a tree hopper has been summarized by 

 Doctor Funkhouser as follows: 



Eggs: Laid in fall, hatch in early spring. 



Nymphs: Emerge about the middle of May and require about six weeks 

 to reach maturity. 



Adults: Are common about July 1 and persist throughout summer and fall. 



Mating: Takes place the first week after emergence. 



Oviposition : Occui"s within a week after mating. 



Broods: Usually one but sometimes more, dependent on weather condi- 

 tions. 



