Lawson: Membkacid.f. of Kansas. 43 



For a single individual the life cycle would be somewhat as follows: 



Egg stage: From SenleiiihiT to middle of May 8V^ months 



First instar 1 week 



Second instar 1 week 



Third instar 1 week 



Fourth instar 1 week 



Fifth instar 2 weeks 



Nymph : 



Total, fniiii middle of May to July 1% months 



Adult : From July to October (inclusive) 4 months 



Entire life 14 months 



The above dates of course apply to New York and would differ 

 somewhat from what occurs in Kansas. 



One of the easiest ways to find certain species of tree hoppers is 

 to notice the more readily seen ants which attend so many of our 

 common forms. In this way Vanduzea triguttata and Entylia con- 

 cisa are very easily located. It is well known that the ants obtain 

 honey dew from these insects, although there are many species of 

 tree hoppers which do not seem to furnish this substance in suffi- 

 cient ciuantity to attract the attention of these visitors. 



It is well known that these insects are frequently parasitized. 

 Hymeqopterous parasites of the family Dryinidae have been known 

 to occur in several genera of tree hoppers. Doctor Kornhauser 

 worked out in great detail the life history of such a parasite, 

 Aphelopiis thelice, which parasitizes Thelia himaculata. In addi- 

 tion, tree hoppers are often the prey of predaceous insects and 

 spiders. Of such predaceous enemies there are a number of kinds, 

 but it is quite doubtful if these enemies are a very vital factor in 

 the natural control of the members of this family. 



ECONOMIC IMPORTANCE. 



The chief damage done by tree hoppers is by their oviposition. 

 The records of injury to young orchards, especially to apple, are 

 many. The type of oviposition that may really be serious is that 

 represented by the egg punctures of Ceresa bubalus, and this species 

 is seemingly the most often accused of all the species concerned. 

 The writer has seen young orchards in which the outer twigs were 

 all roughened up by the oviposition scars, and such cases are numer- 

 ous in the literature. The exact damage done, however, is prob- 

 lematical, many inclining to the opinion that as a rule the damage 

 done is not serious. Others hold that in after years such scars will 

 weaken the branches, causing them to be more easily broken off by 

 the wind, and also furnishing good points of attack for borers. The 



