INSECTS INJURIOUS TO CORN 



161 



three-fourths of an inch long, of the form shown in the illustration, 

 and are of a brown or black color, marked with darker longitudinal 

 ridges on the wing-covers. The larva is a thick fleshy white 

 grub, from one-fourth to five-eighths of an inch long, with a brown 

 head and cervical shield on the first segment, and footless. 



Life History. The life histories of the different species are 

 but partially known. 



FIG. 136. Sphenophorus ochreus, larva, adult, and work in roots of Scirpus. 

 (After F. M. Webster, "Insect Life.") 



S. parvulus hibernates over winter as a beetle, appearing in 

 March and April. The female punctures the stalk of wheat or 

 timothy oats and barley are also sometimes attacked a little 

 above the roots, and deposits her egg in the cavity. This is done 

 in May or June or even up to July 1st. The larvae are to be found 

 during July, becoming full grown and pupating during the latter 

 part of that month. The larvae will eat out quite a cavity in the 

 interior of the stalk or bulb, and then attack the roots, thus often 

 killing a whole clump or stool of small grain or timothy. The 

 pupal stage is passed in a small cell in the earth and lasts from two 

 to three weeks, adult beetles emerging from the middle of August 

 to the first of October. 



