04 MAINE AGRICULTURAL EXPERIMENT STATION. I916. 



nately the color feature^ can not be shown without a color 

 plate. There is sufficient agreement in habit between the thrips 

 and the leafhoppers so that this distinction may be of little 

 economic necessity but infestation from plantlice must be from 

 other sources and in any case there is an advantage in knowing 

 the exact nature of the insect that may be most prevalent in 

 any community or field so that such preventive measures as 

 may be possible may be applied intelligently. 



Another means of identification for the leafhoppers where 

 the living insects cannot be found or where no eggs are evident 

 is found in the presence of the moulted skins of the nymphs. 

 These retain the form and show the characters of the nymphs 

 and as they remain attached to the leaves, often for some time 

 after the emergence of the insect, they are a good proof of the 

 presence of leafhoppers. Their absence however cannot be con- 

 sidered as proof of no hoppers as they are not firmly attached 

 to the leaves and are easily dislodged by shaking or the brush- 

 ing of leaves together in the wind. The series of photographs 

 of these moulted skins, Fig. n, will assist in the identification 

 and they may be readily examined with the aid of a low power 

 lens. 



Life History. 



There is considerable irregularity in the life history of 

 this species and it is difficult to state any definite periods for 

 "the development of the stages especially if any large area of 

 country is considered. In Maine adults are to be found in plenty 

 iu late June and early July and there is a pretty well marked 

 btood occurring in July, which is found abundantly in oat fields, 

 and it is this brood which has been the basis for our mo&t 

 definite records as to length of instars and rate of growth. 

 Adults were found with developed eggs July ioth, and from 

 these eggs were dissected for comparison with eggs deposited 

 in the plants, and eggs from adults confined on oat plants in 

 the insectary were laid about the 16th and began hatching on 

 the 23rd. 



The eggs were laid in the leaf sheath and at base of leaf 

 blade and a little tuft of white strands mark the place of punc- 

 ture. The egg lies head end to the opening and in a short time 

 the eyes become quite conspicuous. The eggs often lie in close 



