July 15, 1925 
Effect of Low Temperatures on Bruchus oitectus 
181 
length of time required for a complete life cycle. This means that 
even in the South development of the insect could be retarded con¬ 
siderably until fatal outdoor temperatures prevailed. 
CONCLUSIONS 
Bruchus obtectus Say dies if the heat of crystallization is given off. 
A definite correlation exists between supercooling and rebound, 
which is believed due to radiation. The electrothermal method does 
not give the true freezing point of an insect because of radiation and 
the effect of injury on the insect. There is no correlation between 
supercooling points and the time required to bring the insect to these 
points. 
The capacity of Bruchus obtectus to resist low temperature is lim¬ 
ited by the length of time it can remain in the supercooled condition. 
This capacity varies with the stage, active adults being least re¬ 
sistant and eggs most resistant. 
Growth of Bruchus obtectus in beans can be materially retarded by 
storage in temperatures even as high as 64° F. Temperatures of be¬ 
low —10° C. for a period of 12 hours are fatal to all stages of this 
insect. 
LITERATURE CITED 
(1) Bachmetjew, P. 
1899. UBER DIE TEMPERATUR DER INSEKTEN NACH BEOBACHTUNGEN IN 
btjlgarien. Ztschr. Wiss. Zool. 66: 521-604, illus. 
1901-07. EXPERIMENTELLE ENTOMOLOGISCHE STUDIEN. 2 V. Leipzig 
and Sophia. 
(3) De Ong, E. R. 
1921. cold storage control of insects. Jour. Econ. Ent. 14 : 444^-447. 
(4) Duval, M., and Portier, P. 
1922. LIMITE DE RESISTANCE AU FROID DES CHENILLES DE COSSUS COSSUS. 
Compt. Rend. Soc. Biol. [Paris] 86: 2-4. 
(5) Garman, H. 
1917. OBSERVATIONS AND EXPERIMENTS ON THE BEAN AND PEA WEEVILS 
in Kentucky. Ky. Agr. Exp. Sta. Bul. 213: 309-333, illus. 
(6) Harvey, R. B. 
1919. importance of epidermal coverings. Bot. Gaz. 67: 441-444. 
(7) Hine, J. S. 
1908. SOME OBSERVATIONS CONCERNING THE EFFECTS OF FREEZING ON 
insect larvae. Ohio Nat. 8: 258-260. 
(8) Houlbert, C. V. 
1920. les insectes. Ed. 2, 374 p., illus. Paris. 
(9) Knight, H. H. 
1923. STUDIES ON THE LIFE HISTORY AND BIOLOGY OF PERILLUS BIOCU- 
LATUS FABR., INCLUDING OBSERVATIONS ON THE NATURE OF THE COLOR 
pattern. Rpt. State Ent. Minn. (1922) 19: 50-96, illus. 
(10) Larson, A. O., and Simmons, P. 
1924. INSECTICIDAL EFFECT OF COLD STORAGE ON BEAN WEEVILS. Jour. 
Agr. Research 27: 99-105. 
(11) Morgan, J. L. R. 
1908. THE ELEMENTS OF PHYSICAL CHEMISTRY. Ed. 4, 539 p., illus. 
New York and London. 
(12) Pearson, K. 
1897. regression, heredity, and panmixia. Phil. Trans. Roy. Soc. 
London (A) (1896) 187: 253-318. 
(13) Pirsch, G. B. 
1923. STUDIES ON THE TEMPERATURE OF INDIVIDUAL INSECTS, WITH 
special reference to the honey bee. Jour. Agr, Research 24: 
275-288, illus. 
