378 
JOURNAL OF ECONOMIC ENTOMOLOGY 
[Vol. 11 
Description of Puparium 
The puparia average 5 mm. in length and 1.25 mm. in width. Both 
the posterior and anterior spiracles are present in practically the same 
form as in the larval stage. The surface of the puparium is grooved by 
wavy transverse lines. The thoracic and abdominal segments are 
indicated by deeper grooves in which the coloring is decidedly darker. 
Along each side are seven narrow, oval depressions, occurring at the 
segmental divisions and enclosed by dark brown lines. 
Hibernation 
C. glabra hibernates as a puparium in the soil where the larva com¬ 
pleted feeding. The puparia become increasingly abundant during 
late August and September and by the last of October no other stage 
can be found. Repeated examinations of root-louse colonies in the 
late fall and early spring have failed to give evidence of hibernation in 
any form other than the puparium. A large proportion of the puparia 
hibernate successfully. Out of 360 puparia collected early in May, 
266 or 74.4 per cent, transformed to adults. 
Seasonal History 
The adults emerge from overwintering puparia during a period ex¬ 
tending approximately from May 15 to June 15. Adults are abundant 
in the open from June 1 until late in September. During the last of 
August they become scarce in lawn grass but are abundant in the 
vicinity of sugar-beets and Chenopodium. 
In 1916 the first eggs were found in the breeding cage July 22, 
and outdoors July 29. Eggs were plentiful throughout the month of 
August. On September 5, only empty egg shells could be found and 
dissections of females indicated that egg laying was practically over. 
Out of 25 females examined on this date only 2 contained eggs. 
Larvae were first observed indoors on July 25 and outdoors August 
2. In observations of sugar-beet root-louse colonies during the last 
seven years the maggots have never been noticed in abundance in the 
field until the middle of August. 
The larvae were at the height of their abundance during the last 
week of August. Practically all the larvae had pupated by September 
21, although several maggots were found during the month of October. 
The first puparia were obtained indoors August 12 and outdoors 
August 21. On the latter date upon examining the crowns and roots 
of Chenopodium plants all stages of the fly were found; eggs about the 
crowns; all sizes of larvae and occasional puparia among the roots. 
From this date the number of puparia gradually increased. During 
the first week in September about as many puparia as larvae could be 
