Insects Visiting Blossoms of Spirea 143 
larvee and pupee which are about ready to transform, in such 
a manner as to postpone the completion of their hfe cycle 
until the following summer. This latter is in line with 
numerous observations of the author which show that the 
duration of the life history of many species of boring insects 
is subject to considerable variation, due often to apparently 
only small differences in the environmental conditions. 
My thanks are due to several men for the assistance they 
have given by identifying specimens. I wish to thank Dr. 
Harry P. Brown of the Department of Dendrology of this 
college, for identifying the several plants mentioned; Prof. 
C. J. Drake, my colleague in the Department of Entomology 
of this college for naming the Hemiptera; Prof. J. S. Hine 
of the Department of Zoology and Entomology, Ohio State 
University, for naming the flies, and Mr. M. R. Smith of 
the Bureau of Entomology, U. S. Department of Agricul- 
ture, Baton Rouge, La., for identifying the ants. 
