46 INSECTS AFFECTING STORED PRODUCTS. 
GENERAL CONCLUSIONS. 
The results of the series of experiments performed with bisulphid 
of carbon and hydrocyanic-acid gas against the lesser grain-borer, 
and incidentally against other insects, are of considerable value and 
show in brief the following: 
That the lesser grain-borer possesses less resistant power to both 
gases than do most other stored-product insects. 
That fumigations in low temperatures, and especially below 50° F., 
are practically ineffective unless an excessively large amount of bisul- 
phid of carbon or of a cyanid be used, and that it is still more desir- 
able that from 48 hours to 3 days be the length of exposure in order 
to kill all insects in even tight inclosures. 
Experiment No. 8 shows that even with 10 pounds of bisulphid of 
carbon to 1,000 cubic feet of space in a tight receptacle only a very 
small percentage of grain insects were killed in an exposure of 24 
hours and witha temperature of about 48° F., and Experiment No. 10 
shows that even with 20 pounds of carbon bisulphid to 1,000 cubic 
feet, or 10 times what may now be accepted as a standard, only 75 per 
cent of the insects present were destroyed in a 24-hour exposure. 
It may be safely assumed that under ordinary conditions, in mod- 
erately high temperatures, between 65° and 75° F., 14 pounds of 
bisulphid of carbon to 1,000 cubic feet of air space is insufficient 
even for 48 hours’ exposure, and that we may adopt as a general 
standard 2 pounds to 1,000 cubic feet for 48 hours or more, or until 
the odor of the gas has become entirely dissipated. 
BIBLIOGRAPHY. 
1. Fapricius, J. C.——Entomologia Systematica, vol. 1, pt. 2, p. 359, 1792. 
Original description as Synodendron dominica from South America. 
2. Fasricius, J. C.—Entomologice Systematicee Supplementum, vol. 1, p. 156, 
1798. 
Redescription of the species as 8. pusillum, from India. 
3. KIRBY AND SPENCE.—Introduction to entomology, vol. 1; p. 282, 1822. 
Mention of the insect’s eating the roots of rhubarb. 
4. Strepuens, J. F.—Illustrations of British entomology, vol. 3, p. 854, 1880. 
Short technical description. ‘‘ Frequently taken in roots and seeds from 
India.”’ 
5. Lucas, Hrprpotyrr.—L’Histoire Naturelle des Anitmaux Articulés de l’Algerie, 
I, Coléoptéres, p. 468, 1849. 
6. WoL.LaAston, T. V.—Insecta Maderensia, pp. 287-288, 1854. 
Detailed description of genus and species with references and notes. 
aol 
MortscHULsky, V.—Htudes Entomologiques, p. 78, 1857. 
Mentions occurrence of what is without doubt this species in grain in 
Egypt, ete. 
LeConte, J. L.—Classification of the Coleoptera of North America (Smith- 
sonian Institution), Part I, p. 208, 1861. 
Introduced in specimens of wheat distributed from the Patent Office. 
9. REDTENBACHER, L.—Fauna Austriaca, Part II, p, 67, 1874. 
Description and notes. 
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