NOTES ON RECENT RESEARCH. 



25a 



"With a little careful observation most of the 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. 



Method of Treatment. — The treatment consists in making one or more 

 holes in the nest with a stick, and pouring into each hole one or two 

 ounces of carbon bisulphide. The hole may ba closed immediately by 

 stepping on it, or, as many writers suggest, the vapour may be exploded 

 at the mouth of the hole with a match in order to drive the fumes deeper 

 in the chamber. If the latter method is adopted the hole should be 

 covered with fresh earth immediately after the explosion in order to put 

 out the fire and confine the fumes. If this is not done a large portion of 

 the gas will be burned and the efficiency of the treatment be lessened 

 thereby. Right at this point an added word of caution must be given. 

 After the explosion the vapour continues to burn with a colourless flame. 

 It is therefore invisible, but its presence may be easily perceived by hold- 

 ing the hand over the opening or blowing into it. This point should be 

 carefully noted, for if the operator, thinking the fire had ceased and 

 desiring to make an examination of the insects doubly certain, should 

 attempt to recharge the hole from a can or a bottle an explosion would 

 surely follow, with possible fatal results. Explosion does not appear to 

 add to the efficacy of the treatment and is not at all necessary. If it is 

 not attempted it may be well to cover the nest with a wet blanket, which 

 will greatly aid in confining the fumes. If any considerable area is 

 infested, as is often the case in lawns, the holes should not be more 

 than H ft. apart each way, and after the close of the application the 

 surface may be thoroughly watered, as the wet surface will add to the 

 efficiency of the treatment by preventing the rapid diffusion of the fumes 

 into the air. 



Other Subterranean Uses. 



The vapour of carbon bisulphide applied at the rates previously 

 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 vapour of 

 carbon bisulphide is fatal to animal life of all forms if inhaled in sufficient 

 quantity. Within recent years this chemical has come into quite exten- 

 sive 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 know- 

 ledge that this agent is by far the safest and most efficient known for the 

 destruction of prairie dogs, gophers, pocket gophers, ground squirrels, 

 wood chunks, moles, and other pests having similar burrowing habits. 

 The subject is quite an extensive one, and as it is now being given con- 

 sideration by the division of Biological Survey, and does not properly come 



