LIFE HISTORY NOTES ON THE PLUM CURCULIO IN IOWA. 
Conotrachelus nenuphar Herbst. 
BY R. L. WEBSTER. 
During the summer of 1910 some insectary experiments were made at 
Ames with the plum curculio in apples, but since these were few, and of 
no great importance, no mention of them was made in print. However, 
when taken in connection with some notes on the insect made in 1889 by 
Prof. C. P. Gillette, then entomologist of the Iowa experiment station, 
these stray notes become somewhat more valuable, as they fit in nicely 
with the notes taken by Professor Gillette.* Since little definite data 
concerning the seasonal history of this insect in Iowa is available, these 
notes are incorporated in the present paper. The 1910 notes were made 
by Mr. T. M. McCall, insectary assistant at that time, and by the writer ; 
most of them by the former. These notes are from the insectary records 
of the entomological section of th.e agricultural experiment station at 
Ames. 
In the spring of 1889 at Ames Prof. Gillette jarred plum trees and 
examined fruit every few days from April 25 to May 14, but found 
neither the beetles nor their punctures. After May 14 only the fruit 
was examined and this was done nearly every day until May 25, when 
the first punctures were found. On June 12 Professor Gillette estimated 
that “the majority of the eggs then laid were still unhatched, ” and on 
June 18 he observed that nearly half of the punctures contained eggs 
yet unhatched. By June 19 larvae 3-16 inch long were found. June 24 
eggs were still present but by this time were becoming more and more 
rare. Some larvae were then nearly mature. Again on June 26 and also 
on June 28 a single egg was found. However, as late as July 22 and 24, 
1889, Professor Gillette found some eggs in plums, but these were evi- 
dently deposited by overwintering beetles. 
In 1910 Mr. McCall- and the writer collected apples badly infested with 
curculio larvae and placed them in jars in the insectary. These apples 
were collected in an orchard near Ames on June 13 and 28 and July 5 
and 23, so are sufficiently scattered that the roarings from these should 
*Iowa Agr. Exp. Sta. Bui. 9. p. 371. 
