1963] 
Bailey — Tingidae 
215 
limitations of this method were suggested in the report cited above. 
On the whole it gives very satisfactory results for these relatively 
sedentary arboreal and thamnophilous species when at least mod- 
erately abundant. When the host plant is small or the lace bug 
population somewhat sparse, the attrition from collecting alone 
could undoubtedly influence seasonal trends. Throughout the period 
of these studies there is no evidence that this was a significant factor. 
During the 1957 season, pilot studies were made in the area de- 
scribed above to determine the number of species of Tingidae pres- 
ent and to tentatively locate host plant stations supporting sizeable 
lace bug populations. This initial survey revealed at least ten resi- 
dent species. Of these, seven were in the genus Corythucha and one 
each in the genera Corythaica , Acalypta , and Leptopharsa. Collections 
were made at approximately weekly intervals. At the end of the 
season analysis of the field work indicated profitable population 
studies could be made for Corythucha juglandis (Fitch), C. mollicula 
O. & D., and C. pergandei Heidemann. These studies were, there- 
fore, continued during 1958 and i960. In the course of this work 
other observations were made and will be reported. 
II. SEASONAL POPULATION TRENDS 
and Other Notes Concerning the Willow Lace Bug 
( Corythucha mollicula Osborn and Drake) 
Among the stations chosen as a result of the 1957 survey was a 
shrubby clump of Salix growing on the northeastern edge of the 
swamp and only five or six yards from the shelter belt of trees de- 
scribed above. This clump of willows is about 10' tall and is sur- 
rounded by other willows, trembling aspens, young oaks and elms, 
gray birch, alders (some appreciably taller) with a lush undergrowth 
of such shrubs as wild roses, Spiraea and Viburnum species, while 
such ferns as the Sensitive, Royal, Cinnamon, and Interrupted along 
with Iris versicolor L. and sedges grow rankly amongst them. On 
the edge of the woods the vegetation changes to include Bteridium, 
Lysimachia , along with various sedges, grasses, a small tangle of 
Srnilax herbacea L. and other herbs which form a generally more 
open ground cover. 
I he host selected supported fair numbers of C. mollicula in 1957 
and collections were started on May 21st. Such collections were made 
fairly regularly in 1957, but not strictly at weekly intervals as in 
1958 and i960. In 1957 no specimens were taken after August 20th. 
Two observations made in 1957 were essentially confirmed by the 
field studies of subsequent seasons. First, although shrubby willows 
