84 
common house ants, except the little red house ants, can usually 
be traced to their homes out of doors. The only effectual way 
of stopping the annoyance or injury from these Insects is to 
destroy the queens living in the nests which they never leave. 
OTHER SUBTERRANEAN USES. 
The vapor of carbon bisulphid applied at the rates pre- 
viously recommended is said to have a marked action against 
certain cryptogamic parasites of plants, though its influence 
in this direction does not appear to have been much studied. 
It is also said to be fatal to the nematode worms, which are 
frequently injurious. In greenhouses these would seem to be 
particularly susceptible to effective treatment. The vapor of 
carbon bisulphid is fatal to animal life of all forms if inhaled 
in sufficient quantity. Within recent years this chemical has 
come into quite extensive and successful use against a class of 
small mammals which are common nuisances, if not actual pests, 
in many parts of the country, and particularly in the West. To 
Prof. E. W. Hilgard, of the University of California, is given 
the credit of being the first to employ this remedy against ground 
squirrels and gophers.* It is a matter of common knowledge 
that this agent is by far the safest and most efficient known 
for the destruction of prairie dogs, gophers, pocket gophers, 
ground squirrels, woodchucks, moles and other pests having 
similar burrowing habits. The subject is quite an extensive one, 
and as it is now being given consideration by the Division of 
Biological Survey, and does not properly come within the pro- 
vince of the Division of Entomology, further comments here 
are unnecessary. 
*Bul. 32, Univ. Cal., “On the Destruction of the Ground Squirrel 
by the use of Bisulphide of Carbon,” 1878. 
DESTROYING BORERS IN TRUNKS OF TREES. 
Considerable has been written in favor of this use of carbon 
bisulphid. It is apparent that only the large borers which work 
in the trunks and lower branches of trees will be good subjects 
for this treatment. There are usually but few of these in each 
trunk, and the outlets of such burrows as contain active borers 
are usually marked by the sawdust and castings which the borers 
throw out therefrom. Only these burrows should be treated. 
Clean-cut, empty holes in the truuk indicate that the insect has 
become adult and left the tree. It is, therefore, a useless waste 
to inject the liquid into, such holes. In peach, plum, apricot and 
cherry trees (all stone fruits), an abundant exudation of sap 
through the outlet of the burrow causes a ball of gum, mixea 
with castings, to collect around the hole. This should be 
scraped off before the treatment is applied. 
Method of treatment. — Having cleaned out the mouth of the 
hole as well as possible, inject a small quantity of carbon bisul- 
phid and close the hole tightly with a little grafting wax. This 
will quickly kill the borer and will not injure the tree; it also 
saves the additional injury which would necessarily be made in 
cutting out the borer. The saving of time alone will fully pay 
for the small amount of carbon bisulphide required. The liquid 
may be conveniently applied by means of a spring-bottomed 
oil can. 
