1928] 
Effect of Extreme Temperature on Criocerus 
229 
THE EFFECT OF THE EXTREME TEMPERATURE OF 
DEC. 7, 8, AND 9, 1927 ON HIBERNATING CRIOCERIS 
ASPARAGI L. AND HIPPODAMIA CONVERGENS 
OTTER. AT AMES, IOWA 
By Randall Latta 
Ames, Iowa 
During the early winter of 1927 at Ames, Iowa, the tem- 
perature dropped suddenly on Dec. 6 from 26°F to7° the follow- 
ing day, to — 25° on the 8th and then rose again to — 8° on the 
9th. A small amount of snow had previous^ fallen, but was 
mostly in drifts, leaving many places exposed. 
Field observations following this period proved that Hippo- 
damia convergens Guer., a common coccinellid and Crioceris as- 
paragi L. the asparagus beetle, were not able to withstand this 
unusual temperature. 
Hippodamia convergens is probably the most common cocci- 
nellid in the vicinity of Ames, Iowa. Large numbers of them, as 
well as lesser quantities of other species of ladybirds, gathered in 
late summer at a turnip patch on a truck farm at the outskirts of 
Ames, to feed on the aphids there. As fall advanced the beetles 
hibernated in the sod fencerow at the edge of the turnip field. 
In the latter part of December the above mentioned fence- 
row was examined and a 100% mortality found. In a space 6 
feet long and one foot wide immediately bordering the turnip 
patch 26 dead H. convergens were counted. An open crevice of a 
fencepost held 50 dead ladybirds of this species, and between 50 
and 75 dead specimens were removed from beneath a stone at the 
same place. At the same time living specimens of H. parenthesis, 
H. 13-pundata and Coccinella 9 -notata were found active among 
the dead H. convergens . 
Other observations made later supported the above findings. 
At a highland prairie northwest of Gilbert, Iowa, nearly 40 dead 
H. convergens were uncovered beneath stones, and at the time 
living H. 13 -punctata and H. parenthesis were collected. 
In the spring of 1928, Hippodamia 13 -punctata and H. pa- 
