THE MAIZE BILLBUG. 19 
of its own accord. Sometimes there are three or four larvee in the 
same plant, their burrows often running into each other, but this 
does not appear to discommede them in the least, as they can, and 
usually do, all mature. In badly infested fields two larve are quite 
often in the same plant, although one is the usual number and is 
sufficient to ruin the plant. The larve are easily managed in the 
laboratory; upon issuing from the eggshell they can be readily 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 larve must be removed 
to fresh sections; keeping them thus sup- 
phed with fresh food they can be reared to 
maturity. 
The length of the larval tife ranges from 
40 to 50 days, as indicated by laboratory 
observations and checked by collections in 
the field. They begin maturing and pu- 
pating by the Ist of August, pupation 
reaching the maximum by the 20th. and 
with the exception of a few stragglers all 
are mature and changed to pupx by the 
Ist of September. 
THE PUPA. 
(Fig. 9.) 
The larve, 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 'F'6- 9—The maize billbug: 
x Pupa: a, ventral view; 6b, 
they construct a cell where they inclose dorsal, view: c, anal seg- 

themselves for pupation. ment; d, thoracic spiracle ; 
= 2 ‘ e€, abdominal spiracle. a, Db, 
The newly issued pupex are white, becom- Twice natural size; c, d, ¢, 
ing darker after the fourth or fifth day, and Pay enlarged. (Origi- 
¥ nal.) 
continue to darken until just before the 
adults issue. The adults are reddish black in color. The length of 
living pup 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. ro- 
bustus, from the single individual collected by Dr. Howard at 
Columbia, S. C.:4 
Average length, 17 millimeters. Stout, rostrum reaching between first pair 
of tarsi. Antenne but slightly elbowed and reaching not quite to bend of 



¢ Loe. ecit., p. 142. 
