170 MAINE AGRICULTURAL EXPERIMENT STATION. I905. 



number of eggs in a sac (600 to 700), the lively disposition of 

 the young scales and their ability to travel, and the fact that 

 there are at least two broods a season, all indicate. 



The insidious approach of this insect may be illustrated by 

 this experience. During the late summer and early fall of 1904 

 in the vicinity of Orono, careful searches were made for egg 

 sacs over large areas, some of which appeared to be entirely 

 free from the scale and others attacked in an exceedingly scat- 

 tering manner. This fall, 1905, the increase in the places of 

 scattering infestation is very marked, and even over some areas 

 apparently free last season the egg sacs are a common though 

 not yet a conspicuous occurrence. In one Orono meadow which 

 contained an infested plot last fall, the egg sacs have increased 

 certainly one hundred fold in a year's time. 



NATURAL CHECKS. 



Whether such increases are occasions for real alarm is a ques- 

 tion involving a consideration of natural agencies as checks. 



Weather. — While the eggs within the sacs are safe in ordi- 

 nary climatic conditions, the young larvae, minute, delicate, and 

 unprotected, must be largely dependent upon favorable condi- 

 tions between the time of leaving the sac and settling upon a 

 promising blade. A heavy rain at this time must undoubtedly 

 beat down and destroy myriads of the little creatures. 



Rust. — In a meadow near Portland thickly infested with the 

 scales, areas half a mile in length were observed to be attacked 

 heavily by rust. This was the 25th of August, 1904, when 

 many of the scales were from one to three weeks old. The 

 situation of the rust spots along the leaf resembled so closely 

 the position selected by the scales that it suggested the possibility 

 of some relation between the rust and the scales. In view of the 

 fact that fungi are predisposed to attack parts of plants wounded 

 by insects or in other ways, it seems legitimate to conclude that 

 the grass rusts in scale infested meadows would be most likely 

 to settle at places punctured by the scales. The development of 

 rust could not but interfere with the scales upon the same leaf, 

 and death of the scales result indirectly from the presence of the 

 rust. It was an interesting, if not a significant circumstance, 

 that in the Portland meadow the rust was much more conspic- 



