44 
THE SUGAE-BEET WIEEWOEM. 
after the &3t rains, is quite thorough, averaging from 10 to 14 inches 
deep, and as the soil is damp and mellow at this time very few clods 
are left. This treatment disturbs most of the beetles, and these, 
unless the weather is too severe, may come to the surface and finish 
their hibernation in any sheltered place they can find. If the weather 
is severe and cold many of the beetles prefer to remain in the soil. 
It is due to these conditions that there is a variation in the time of 
appearance of the adults, as has been proven by systematic collec- 
tion in the fields. 
Collections were made in some of the fields day after day and 
tabulated. The beets which sheltered adults every day were marked, 
and the beetles which were collected from them every day were 
noted. The following table gives the number of beetles which were 
taken from under the same beet on the dates given: 
Table I. — Emergence of adults of the sugar-beet u-ireu-orm from hibernation in the field. 
Date. 
Xamber of 
beetles. 
^■'''- ""iSies."' 
Feb. 29 
Mar 1 
2 
1 
7 
3 
17 
2 
1 
1 

29 
47 
13 
Mar.l2 4 
Mar 13 7 
Mar 2 
Mar. 14 . 1 
Mar.3. 
Mai. 4 
Mar.o 
Mar. G 
Mar. 7 
Mar.lo 3 
Mar. 16 SO 
Mar. 17 11 
Mar.lS 
Mar. 19 •'> 
Mar. 8 
Mar. 23 1 
Mar. 9 
Mar. 24 srt 
Mar.lO 
Mai. 11 
Mar.2(i 9 
As these notes were tuken before the beetles were moving through 
the fi.eid very generally, it appears that the latter must have come 
from the soil near the beets which were used for hibernating cpiarters. 
Secoxdary Hibeexatiox. 
The beetles which are driven to the surface prematiu'ely seek what 
may be termed "secondary hibernation'' imder ahncst any shelter 
which can be found. The substances in the following Hst, under 
which beetles were foimd, are named in about the order of prefer- 
ence: 
(1) Left-over beets. 
(2) Old beet tops. 
(3) Wild beet roots. • 
(4) Alfalfa roots. 
(5) Johnson grass roots (Sorghum hale- 
pense). 
(6) Lambsquarters (Chenopodium sp.). 
(7) Pigweed stalks {Amaranthus retro- 
flexus) . 
(8) Wood. 
(9) Clods. 
(10) Cracks in soil. 
(11) Old sacks. 
(12) Manure. 
(13) ^liscellaneoiis rubbish. 
