AQUATIC INSECTS IN NEW YORK STATE 



445 



The masses are often quadrangular but are variable in out- 

 line, and are not coated with any protecting material. Several 

 masses are very commonly found near each other; in one case 

 about 150 masses were found within an area 6 by 12 inches; and 

 the remains of the masses of former years are also found near 

 the fresh eggs if the place be a suitable one. The eggs are all 

 placed in a slanting position, i. e. not perpendicular to the sur- 

 face of attachment; and are all parallel to each other, in one 

 layer, with the micropylar projection outward. Exact counts 

 and estimates show that the number of eggs in a mass is usually 

 from 200 to 500 [pi. 51]. 



Life history of Sialis infumata 



It is an interesting sight to see a female depositing her eggs. 

 This I have witnessed on several occasions. 

 She deposits an entire row of 10 to 20 eggs 

 and then begins another row; as the rows 

 accumulate, she moves backward over the 

 mass to reach the place for the succeeding 

 rows; thus her body and wings cover the 

 egg mass till it is completed. The eggs are 

 always deposited over water or in a place 

 where the young larvae will naturally fall 

 into water. 1 found them on the under 

 sides of boat landings, on the under and 

 vertical sides of bridges, on stones project- 

 ing above the water of creeks and lakes. 

 Stagnant pools are not attractive to mem- 

 bers of this genus. The adults do not seem 

 to select the twigs or leaves of trees and 

 shrubs when such objects as those above 

 mentioned are accessible. When a high 



bridge is selected by the adults, on which ^.^ ^^ ^^^,^ „, g,^„^ 

 to deposit their eggs, they know where the ilLV'" "' ^^"^ """'" 

 limits of the running water are, and deposit the eggs within 

 those limits. 



After seeing females deposit their eggs and after noting the 

 dates when other new eggs were deposited, say on a given rock, 



