INSECTS INJURIOUS TO CORN 



179 



history upon the corn-plant, so that the common name given it 

 appropriately distinguishes it from the other bill-bugs previously 

 mentioned. It has, however, been found feeding and p'robably 

 breeding in swamp-grass (Tnpsacum dactyloides) , which may be 

 its native food plant. 



Life History. The eggs were found in southern Kansas during 

 June, laid in punctures made by the female in young corn- plants. 

 These egg punctures are mere slits 

 and do not seem to materially injure 

 the plant. The eggs hatch in from 

 seven to twelve days, and from 

 them emerge small footless, dingy 

 white grubs, with chestnut-brown 

 heads, of the appearance shown 

 in Fig. 132. " They at once begin 

 feeding on the tissues of the young 

 corn at the bottom of the egg 

 puncture, directing their burrow 

 inward and downward into the tap- 

 root. When they finish eating the 

 tender parts of the taproot they 

 direct their feeding upward, con- 

 tinuing until full grown, allowing 

 thelower portion of the burrow to 

 catch the frass and excrement. 

 This burrowing of the taproot of the 

 young growing corn-plant is disastrous to the root system; . . . 

 allowing it to die or become more or less dwarfed." Often the 

 young larvae burrow into the heart of the plant and cut off 

 the growing bud, thus killing the top. The larvae become full 

 grown early in August, when they are about four-fifths of an inch 

 long. ' The larvae, on finishing their growth, descend to the lower 

 part of the burrow, to the crown of the taproot, cutting the pith 

 of the cornstalk into fine shreds, with which they construct a cell 

 where they inclose themselves for pupation." The pupae are to 

 be found in these cells in late August and early September, the 



FIG. 131. The maize bill-bug 

 (Sphenophorus maidis Chittn.) 

 four times natural size. 

 (After Keliy, U. S. Dept. Agr.) 



