THE MAIZE BILLBUG. 



19 



of its own accord. Sometimes there are three or four larvae in the 

 same plant, their burrows often running into each other, but this 

 does not appear to discommode them in the least, as they can, and 

 usually do, all mature. In badly infested fields two larva? are quite 

 often in the same plant, although one is the usual number and is 

 sufficient to ruin the plant. The larvae are easily managed in the 

 iaborator}^; upon issuing from the eggshell they can be readity han- 

 dled with a soft camel's-hair brush and placed inside a section of 

 a cornstalk, where they will feed as readily as upon the growing 

 plant. As soon as the section of plant is fairly eaten, and before 

 decay sets in, the larvae must be removed 

 to fresh sections; keeping them thus sup- 

 plied with fresh food they can be reared to 

 maturity. 



The length of the larval life ranges from 

 40 to 50 days, as indicated by laboratory 

 observations and checked by collections in 

 the field. Thej^ begin maturing and pu- 

 pating by the 1st of August, pupation 

 reaching the maximum by the 20th, and 

 with the exception of a few stragglers all 

 are mature and changed to pupa; by the 

 1st of September. 



THE PUPA. 



(Fig. 9.) 



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 newly issued pupa? are white, becom- 

 ing darker after the fourth or fifth day, and 

 continue to darken until just before the 

 adults issue. The adults are reddish black in color. The length of 

 living pupae ranges from 16 to 20 mm. 



The following description of the pupa was made by Mr. E. A. 

 Schwarz, of the Bureau of Entomology, under the name of S. to- 

 Vastus, from the single individual collected by Dr. Howard at 

 Columbia, S. C. : a 



Average length, 17 millimeters. Stout, rostrum reaching between first pair 

 of tarsi. Antennae but slightly elbowed and reaching not quite to bend of 



Pupa : a, ventral view ; J) x 

 dorsal, view ; c, anal seg- 

 ment ; d, thoracic spiracle ; 

 e, abdominal spiracle. a, b, 

 Twice natural size ; c, d, e,. 

 greatly enlarged. (Origi- 

 nal.) 



Loc. cit., p. 142. 



