46 INSECTS AFFECTING STOKED 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 with a 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., 1-J 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. Fabricius, J. C. — Entoruologia Systematica, vol. 1. pt. 2. p. 359, 1792. 
Original description as Synodendron dominica from South America. 
2. Fabricius, J. C. — Entomological Systematica^ Supplenientuin, vol. 1, p. 156, 
1798. 
Redescription of the species as S. pusillum, from India. 
3. Kirby and Spence. — Introduction to entomology, vol. 1, p. 232, 1822. 
Mention of the insect's eating the roots of rhubarb. 
4. Stephens, J. F. — Illustrations of British entomology, vol.. 3, p. 354, 1830. 
Short technical description. " Frequently taken in roots and seeds from 
India." 
5. Lucas, Hippolyte. — L'Histoire Naturelle des Animaux Articules de l'Algerie, 
I, Coleopteres, p. 468, 1849. 
6. YVollaston, T. V. — Insecta Maderensia, pp. 287-288, 1854. 
Detailed description of genus and species with references and notes. 
7. Motschulsky, V. — Etudes Entomologiques, p. 78, 1857. 
Mentions occurrence of what is without doubt this species in grain in 
Egypt, etc. 
8. 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, 
