Group 1 contains species normally restricted to rivers which have 
rocky beds and such obstructions as bridge piles, piers, and, in time 
of floods, partly submerged trees. These species deposit their eggs 
at the level of the water, or just below, on any convenient surface, 
such as the bare portions of rocks, sunken posts, and collections of 
water- worn debris, always where the current is exceedingly swift. 
Eggs have never been found by the writer on any surface that was not 
smooth or that was at all covered by moss, algse, or other aquatic 
growths. Of the five species whose methods of oviposition are dis- 
cussed in this article, S. pictipes alone belongs in this group. The 
oviposition and early life history of this species were first described 
by Dr. W. S. Barnard in the American Entomologist in 1880. He 
states that the eggs are long ovoid in form, and gives a figure showing 
them deposited in a vertical position. He also states that the young 
larvae were issuing from the eggs deposited on the rocks above the 
water line and were passing down into the water to begin aquatic life. 
If this was the case, the eggs must have been moistened continually 
by the spray and not left in a dry state, as is implied, the reason for 
which surmise will be discussed at length farther on. 
The eggs of this species which were found by the writer seemed 
to have been deposited indiscriminately in a horizontal as well as in 
a vertical position. The angles appeared rather broadly rounded. 
(PL III, fig. 6.) Surrounded by a viscous substance known as the 
matrix, in which they are fairly evenly distributed, they are laid 
normally in masses on the smooth surface of the rocks just below the 
level of the water. The matrix is brownish yellow at first, after- 
wards turning brown. Usually several females will oviposit in the 
same spot, causing the layers to overlap. 
GBOUP 2. 
Group 2 is made up of species which are peculiar to small streams 
with less force of current and with only submerged herbage or occa- 
sional small collections of sticks and stones to serve as a place for 
the attachment of the immature stages. As a general rule the situ- 
ation selected for oviposition is a grass blade bent at right angles and 
trailing just at the surface of the water and with its surface continu- 
ously moistened. 
/S. mttatum almost invariably oviposits on grass blades in small 
streams. The eggs adhere to the grass blades by a creamy viscous 
matrix entirely covering the eggs. This matrix turns yellowish 
brown on the second day and becomes gradually darker until the eggs 
hatch. The eggs are laid in a single layer, as a rule, very closely 
together. Several females often select the same situation and, as in 
the case of pictipes, the layers often overlap one another. 
