10 BULLETIN 892, U. S. DEPARTMENT OF AGRICULTURE. 
LIFE HISTORY. 
In the Arkansas Valley of Colorado and in regions having a simi- 
lar temperature, two full generations or broods and a partial third 
generation occur each year. 
The adult passes through the winter on the surface of the ground 
on or about the alkali areas, under tufts of grass, heaps of dead 
weeds, and other rubbish. The favorite location for hibernation is 
under_tufts of “tickle grass” (Panicum capillare), which occur 
abundantly on alkali areas (Pls. IV, V). Under natural condi- 
tions the majority of the beetles will congregate for hibernation 
under grass tufts or under weeds on these areas, a habit of which we 
may take advantage in controlling the beetles as will be explained 
later on. 3 
The beetles issue from hibernation during March and early April, 
the exact time depending on temperature. The earliest date of emer- 
gence noted at Rocky Ford, Colo., was March 12 and the latest April 
10. Usually the majority of beetles issue during the last days of 
March and the first days of April. The time of emergence corre- 
sponds with the appearance of young Russian thistles, sea-blite, and 
-lamb’s-quarters. On these plants the beetles feed and mate and within 
a short time commence to deposit eggs (Pl. Il). The first eggs 
may be laid during the last days of March and through April, but 
ordinarily the bulk of the eggs is not deposited until the latter part 
of April or in May. The development of the first eggs and larve is 
slow. Under ordinary conditions the majority of the beetles of the 
first generation develop between the last days of May and the 
middle of June. 
The beetles of this generation usually feed for 10 days or two weeks 
and then deposit eggs for the second generation. The bulk of the 
eggs is deposited ee the latter part of June and through July 
and the majority of the beetles develop during the latter part of 
July and early August. During the remainder of the summer the 
beetles occupy the greater portion of their time in feeding. A few 
eggs are usually deposited from which the beetles of a partial third 
generation develop in September or the first days of October. As a 
rule, the number of beetles of the third generation is small and of 
slight importance, although occasionally a considerable number may 
develop about the middle o September. 
In general, reproduction occurs from the last days of March until 
the first days of October, with the period of greatest development 
between the middle of May and the middle of eter 
During September and early October the beetles leave their food 
plants and go into hibernation. Asa rule, the greatest number begin 
hibernation between September 10 and 20. During bright sunny 
