27 



tain kinds of Ichneumon flies {Opliion macrurum Linn.) are also de- 

 stroyed by the gas. On one occasion I obtained a cluster of eggs of a 

 species of Psocus fly (GcBcilius aurantiacus Hagen) that were deposited 

 upon a leaf of a tree before the latter had been treated with the gas, 

 and from these eggs afterwards issued a number of parasitic flies be- 

 longing to the family Proctotrupidre and to the genus Alaptus ; but the 

 species is as yet undescribed. Various kinds of Lady-birds, which are 

 in the tree when the latter is treated with the gas, become stupefied and 

 fall to the ground, but finally recover and are to all appearance none 

 the worse for their temporary loss of consciousness. Birds, lizards, and 

 even barn-yard fowls sometimes refuse to leave the large orange trees 

 while the tent is being let down over them at night, and are therefore 

 inclosed in the tent and subjected to the gas ; the latter proves fatal to 

 all of these. The small, pale yellow mites which are frequently found 

 on orange trees, especially beneath the dead scales, are not affected by 

 the gas; these have a general resemblance to the young of the Eed scale, 

 and several operators, finding these mites still alive after the tree had 

 been subjected to the gas, came to the erroneous conclusion that the 

 gas had not been effectual, thinking that these mites were the young of 

 the Eed scale. 



From the above it will be seen that the gas treatment is not a sure 

 specific for every kind of insect pest, but for destroying Eed scales on 

 citrus trees it is far superior to any other method at present known. 



THE RESIN WASH FOR THE SAN JOSE SCALE. 



During the past winter I carried on quite a series of experiments with 

 various kinds of washes for the destruction of the San Jose scale 

 (Asjndioius perniciosus Oomstock) on dormant deciduous trees, kindly 

 placed at my disposal by Mr. C. H. Eichardson, the inspector of fruit 

 pests for the Pasadena district, Mr. Eichardson also aiding me in mak- 

 ing many of these experiments. Among all of the washes tried the fol- 

 lowing gave the best results : 



Resin pounds . . 30 



Caustic soda (70 per cent) . do 9 



Fish oil pints.. 4£ 



Water, enough to make gallons . . 100 



For making 100 gallons of the above wash a kettle holding 30 gallons 

 will be required. Place all of the ingredients in the kettle and cover 

 with water to a depth of 4 or 5 inches, boil briskly for about 2 hours, or 

 until it will dilute evenly with water, like black coffee, which it closely 

 resembles in color. When this stage is reached the kettle should be 

 filled up with water, adding this very slowly at first ; the contents of 

 the kettle can then be emptied into a tank or other vessel, and a suffi- 

 cient quantity of water added to make 100 gallons. Care should be 

 taken not to chill the wash by adding large quantities of cold water at 

 one time. 



