THE COTTONY GRASS SCALE. I7I 



uous in the places where there were most egg sacs of the grass 

 scale and where the blades must have been freely punctured by 

 the young- scales. Yet on the blades most attacked by the rust 

 no living scales remained. There seemed to be no practical way 

 of obtaining reliable data in this case, but there would be noth- 

 ing extraordinary in a reduction of scales through the weaken- 

 ing of the host plant by fungus agencies. Such a remedy, 

 however, would prove a severe one for the hay crop. 



Predaceoils Insects. — Large numbers of fresH egg sacs were 

 frequently observed (1904 and 1905) to be torn open near the 

 end or at the side, and a considerable portion of the eggs in such 

 cases would be missing. This seemed to be the work of some 

 predaceous insects, but none were observed in the act. 



Overcrowding. — Sometimes more young scales than one leaf 

 could possibly support are found crowded upon a single blade. 

 In such cases death of some of the scales must result, or a dry- 

 ing of the blade which would cause the death of all the scales 

 upon it. 



Parasites. — Nor are parasites lacking. For one test lot 

 nearly two quarts of egg sacs were collected August i, 1904, in 

 a meadow near Portland. On August 3, such numbers of the 

 minute larvae hatched and swarmed over the jars that it seemed 

 improbable that parasites were present to any appreciable extent. 

 Two days later, however, parasitic hymenoptera began to 

 emerge. There were more than 100 of these, among which a 

 new species of Bunotus and a species of a new genus were about 

 evenly represented, and there were a few of a new species of 

 Microterys. About 30 parasitic dipterons, Leucopis nigricornis 

 Egger., a European species, also emerged from this lot. Less 

 than 150 parasites from many thousand sacs, however, would 

 not mean an extended diminution of the scales for that genera- 

 tion. 



The following year, 1905, about the middle of August, egg 

 sacs were collected near Orono for greenhouse observations. 

 These were too extensively parasited to yield a sufficient number 

 of larvae for the experiments planned. From 262 sacs collected 

 about the same time from the Isle of Springs, 98 hymenopterous 

 parasites emerged. No dipterous parasites appeared in this 

 collection. 



