278 JOURNAL OF ECO^fOMIC ENTOMOLOGY [Vol. 14 



will only feed in cora when there is a scarcity of its natiiral food plant, 

 Polygonum hydropiper L. (smartweed) . The larvae burrow into the 

 Polygonum stem and eat their way upward until ready to pupate. 

 The point of entry is a circular opening. The writer has noticed that 

 infested stems prematurely turned red just as older uninfested plants 

 do. It has been said that this turning red has been caused entirely 

 by P. ainsliei. This is apparently not the case, but merely seems as 

 if the process is hastened by the infestation. As many as seven lar- 

 vae have been taken from a single stem in infested fields, although the 

 number usually only ranged from one to three. The nature of the 

 injury to com, which is decidedly imlike that of the European Corn- 

 Borer, has been fully described by W. E. Britton in his Nineteenth 

 Report.^ 



Distribution And Food Plants 



P. ainsliei occurs throughout the Eastern and Middle Western 

 States having been found in Massachusetts, Connecticut, New York, 

 New Jersey, Tennesee, Illinois, Missouri, Kansas and lowa.^ W. P. 

 Flint and J. R. Malloch have published a list of twenty food plants 

 of this species, mentioning the fact, however, that specimens have not 

 been found in any of them except where they were growing near in- 

 fested Polygonum.^ 



Life History At Ames 



Two broods of the insect occur during the season at Ame*-, Iowa. 

 The larvae winter over in their burrows in smartweed after closing 

 the opening with excrement. In the spring they became active for a 

 short time and entered the pupal stage during late May and early June, 

 the moths emerging after a pupal period of from ten to fourteen days 

 during the latter part of May and the first half of June. 



After a short fiight the moths deposited their eggs on the under- 

 side of smartweed leaves in masses containing from eleven to fifty 

 eggs. The writer has not been able to determine the total number of 

 eggs laid by a single female, nor has he been able to induce reared fe- 

 males to deposit eggs in the insectary, but observations upon dissec- 

 tions of females indicate that a single individual deposits several hun- 

 dred. The eggs are glistening white, flat, nearly circular in shape and 

 overlap each other on the leaf at deposition. Daily field trips were 

 made and the first egg masses were observed on Jime tenth, after which 

 they could be found freshly laid until July tenth. The incubation 



