Dec. 1, 1925 
The TJse of Vacuum for Insect Control 
1039 
day) , and that 7 days 7 exposure did not kill all larvae of Attagenus 
piceus, Tenebrio obscurus, and Trogoderma tarsale . 
Additional experiments, in which specimens of these insects were 
exposed to the same vacuum for two days only, gave the following 
results: Larvae of Plodia interpunctellaj Ephestia Tcuehniella , and 
Pyralis farinalisj and adults of Sitophilus oryza and S. granarius 
were all killed. Many larvae and adults of the clothes moth Tineola 
biselliella were killed, but specimens of the other insects were appar¬ 
ently little affected. 
GENERAL OBSERVATIONS 
By using the glass bell jar and the observation windows of the vault 
the activity of the insects in the vacuum chamber could be readily 
observed. It was noted that when the insects were,subjected to a 
29-inch vacuum, all movement ceased in all stages of all species within 
two minutes after the pump was started. Beetles and moths fell 
upon their backs with every appearance of being dead. If the air 
was restored within a short time the insects regained their activity 
and appeared little the worse for their experience, except in the case 
of adults of the meal worm Tenebrio obscurus . The meal-worm 
beetles when treated to this vacuum for only 10 minutes showed 
feeble movements after being restored to the air, but died within a 
few hours thereafter. 
When insects were exposed to the 24 to 28 inch vacuum many 
became inactive soon after the vacuum was obtained but others 
remained slightly active for several days. 
In general, the adult and pupal stages of the insects experimented 
with were more susceptible to the effect of vacuum than were their 
larval stages. Lepidopterous insects were for the most part rather 
easily killed. Treated specimens of the larvae of these and other 
insects were stiff and brittle and appeared to have been thoroughly 
dried out by the process. To test the effect of vacuum on water, a 
small amount Was placed in a glass vial under the bell jar and sub- 
i 'ected to a 29 -inch vacuum; the water boiled violently until the air 
Lad been removed from it. 
Candy, which is often infested with insects, was also treated and 
the effect noted. Chocolate creams were broken open by the force 
of the vacuum, although chocolate-covered nuts were apparently 
uninjured. 
Insects sealed in cartons of breakfast foods and buried in rolls of 
clothing or in upholstered furniture were killed as quickly as though 
they had been exposed in pill boxes or cotton-stoppered glass vials. 
SUMMARY 
9 
A vacuum of 28 to 29 inches, maintained for 7 hours in a bell 
jar of 825 cubic inches capacity when the temperature ranged from 
60° to 70° F. and the barometer read 29.3 inches, killed all adults of 
Alphitobius piceuSj Anthrenus fasciatus, Attagenus piceus , Cryptolestes 
pusilluSj DermestesvulpinuSj Ephestia Tcuehniella , Gnathocerus cornutus, 
G. maxillosus , Necrooia rufipes , OryzaephUus surinamensis , Plodia 
interpunctella, Silvanus gemeltatus , Sitophilus oryza , Tenebrio obscurus , 
Tribolium confusum , and T. ferrugineum . It killed all pupae of 
