LAWSON : KANSAS CICADELLID.^. 11 



reach 18 or 20 mm. in length. Our largest forms are about 

 14 mm. in length, or slightly over half an inch, while our 

 smallest forms are close to one-twelfth of an inch long. The 

 majority or our species run from three to seven millimeters in 

 length, or from about one-eighth to one-fourth of an inch. 



Their small size, coupled with the fact that they dsually 

 remain on the under side of the leaf or blade of grass, accounts 

 very readily for their so easily escaping detection. Then, too. 

 as a rule, they are protectively colored, that is, they usually 

 greatly resemble their surroundings in color. Thus a green 

 species on a green blade of grass may not be seen even though 

 in full view, and when one is looking straight at it. In some 

 species also the art of camouflaging seems to have reached 

 perfection. Though the general coloi.s may not correspond 

 very well with those of the host plant, yet there is a stripe hero 

 or a spot there which seem to be present solely for the purpose 

 of making the insect invisible, at least such is their effect. 

 Some species also, such as Dorycephalu^, show clearly an 

 adaptation of form, as well as color, to their environment. 

 Sitting on a head of Elymus, they so greatly resemble their 

 surroundings as to be practically invisible, and according to 

 Professor Osborn a head of the host may be carefully exam- 

 ined and reveal no insect until it is shaken loose. 



Frequently, too, the damage done by this group of insects is 

 attributed to other insects or to the attacks of fungi. Usually 

 the result of the continued sucking of the life juices of the 

 plant results in more or less discoloration of the plant cells 

 around the puncture. These spots often resemble the spots 

 produced by other insects and may often be mistaken for the 

 presence of some fungous disease. Professor Osborn points 

 out the fact that the work of species infesting grasses and 

 grains may be readily confused with the work of aphids or 

 thrips, but that usually the aphids do not discolor nor produce 

 spots on the infested plant, at least during the early stages. 

 while the injury of the thrips is indicated by small dots or lines 

 which usually run parallel with the leaf veins and remain 

 white. The spot produced by the leaf hopper, on the other 

 hand, while at first pale, later changes to a brown or black 

 color. Furthermore, if the leaf hoppers are the guilty parties, 

 the fact will usually be recognized by the presence o^ theiv 



