156 -MINNESOTA P.ILL BL'GS. 



is certain that two molts occur as their cast skins were found — 

 the second castint^ lieini; found when tlie lar\a was about one- 

 quarter inch in length. 



In the hehl. the lar\al period was found to last from |une 2[) to 

 August 20, and \er_v probably extends well into September; how- 

 ever, the life of an individual lar\a is much less. The occurrence 

 of lar\-ae and pupae as late as ( )ctober ^) is no doubt due to the lont;- 

 egg-laying period. Follo\\ ing this and other obser\ations, the prob- 

 abilities are that this species passes the winter as a pupa or larva, 

 inside of the pupa cell. 



( )n the inside of and near the base of the plant, the larva, when 

 fully grown, makes for itself a somewhat elli])tical cell out of the 

 l)orings. This cell is rounded at either end and almost parallel on 

 the sides. Inside of this, the larva pupates. Scjme time before 

 changing to the adult stage, the pupa gradually changes to a dark 

 brown and remains so even after the adult stage is reached, but 

 later the color turns much darker. ( )ccasionally some of the brown 

 color will remain, even after emergence into the open. From the 

 above information, it is {|uite evident that .S'. z'ciiatiis has but c^ne 

 generation a year in this state. 



Sphenophorus zeae. 



( )n June. l'U3, .V. ccac was found contemporary with .V. voiatiis 

 in all of its habits, at Savage, Minnesota. The owner of the piece 

 of land where mcxst of the observations were made informed me 

 that he distinctly remembers seeing holes in the corn leaves in 

 l'>03 and that he believes he ol)served similar injury in 1(S98. 



Adjoining an area of sedge w'as a held of corn that was very 

 badly infested with 5". iniatiis and 5". rjcac. To the north was a 

 strip of last year's corn left unplowed, while the other half of the 

 held was plowed and seeded to potatoes. \'olunteer specimens of 

 the yellow nutgrass, Cypcnis csciilciitus. was found throughout the 

 potato held in spite of thorough culti\ation. The rows of corn 

 next to the hayfield contained a good deal of the yellow nutgrass 

 wdiich gradually became less as the distance increased. 



On August 20, another visit showed the presence of the eggs 

 and larvae of S. scar in abundance in much of the volunteer sedge 

 in both the cornfield to the west and th.e potato held to the north. 

 Manv empty ])upa cells were found, thus indicating that many 

 adults had emerged. 



As late as October 9. a few larvae and pupae were found in the 

 field, as well as many empty pupa cells. .Ml larvae brought in 



