184 Journal of Agricultural Research voi. xv,no.3 



definitely restricted in its migration, it is of special interest to note that 

 it must be the form which produces pratically all of the eggs. 



In the short-winged form the elytra reach only to the fifth abdominal 

 segment leaving a large part of the abdomen, especially when engorged 

 with eggs, conspicuously exposed. While there is some variation and 

 occasional intermediate forms, there is a great preponderance of indi- 

 viduals with elytra uniformly about 5 mm. long and with the wings still 

 shorter. None have been seen with the wings entirely aborted. 



The relative proportion of eggs produced by the two forms will be dis- 

 cussed under the head of egg production, but it may be said here that 

 from collections made during the summer of 191 6 it appears that only 

 about 10 per cent of the females are long- winged and that these produce 

 a much smaller number of eggs each than the short-winged forms. 



The biologic significance of the dimorphism can hardly be entered on 

 here. It is, however, distinctly similar to what occurs in many other 

 of the Hemiptera and doubtless depends on some fundamental factors 

 in food supply, seasoned migration, or other adaptation. 



It offers many interesting biological problems for investigation and 

 naturally presents some most essential elements in the consideration of 

 general control. 



LIFE HISTORY 



The eggs hatch in May or early June, the time being determined in part 

 by latitude and season. The exact date of hatching at Orono was not 

 observed, as nymphs were already abundant at the time of my arrival on 

 June 12, and as the season of 1916 was exceptionally late, it is probable 

 that the average date of hatching would be the last week in May. Young 

 nymphs continued to appear until about June 25, but none hatched after 

 July I. The first adults appeared on June 16 and were abundant by 

 June 26. 



Evidently the adults feed for some time before mating, as the first 

 matings observed were on July 8 and 10. The eggs, however, develop 

 rapidly when the insects reach the adult stage, since fully developed eggs 

 in large numbers, 50 to 60 to the individual, were dissected from the 

 females, the first one dissected, on June 30, containing 30 eggs fully 

 formed, as well as others in an immature state. Another, dissected on 

 July 8, contained 69 developed and a few immature eggs. 



These dissected eggs were of special interest, as they might furnish the 

 clue to a later determination of place and method of oviposition, as the 

 peculiar strongly curved neck and large membranous expansion over the 

 head naturally suggested some rather unusual mode of placement. 



The nymphs cling closely to the plants and while they pass readily up 

 and down the stems and doubtless shift from one plant to another there 

 is no extended migration, probably no movement providing for any 

 dispersal. When molting, they cling to the plant and, as with other 



