ECONOMIC ZOOLOGY — ENTOMOLOGY. 253 



Spraying injuries, G. E, Stone (Massachusetts Sta. Rpt. 1909, pt. 2, pp. Jt6, 

 Jfl). — ^Attention is called to the noticeable injury during 1909 to apple foliage 

 and fruit from spraying with Bordeaux mixture, and also to foliage burning 

 from arsenate of lead spray, especially on plum trees, but also on maple and 

 beech trees. 



ECONOMIC ZOOLOGY— ENTOMOLOGY. 



The California ground squirrel, C. H. Mebriam ( TJ. S. Dept. Agr., Bur. Biol. 

 Survey Giro. 76, pp. 15, figs. Jf). — This is a more detailed account than that 

 previously noted (E. S. R., 21, p. 153). 



The California gi'ound squirrel, Citellus heecheyi, also known as the Digger, 

 or Beechey ground squirrel, v/hich is of particular importance because of its 

 role in the spread of bubonic plague, ranges from Lassen Butte and Susanville 

 in northeastern California southward, east of the Sacramento Valley to San 

 Francisco Bay, and south of the bay overspreads practically the entire State 

 and pushes southward into the peninsula of Lower California, avoiding only 

 the higher mountains and the more arid deserts. Its subspecies fisheri in- 

 habits Kern and Owens valleys, the borders of the Mohave Desert, the upper parts 

 of San Gorgonio Pass, and other localities in southern California, and occurs 

 as far east as the Coso, Argus, and Panamint mountains. The Douglas ground 

 squirrel (C. donglasi), which ranges from the north side of San Francisco Bay 

 northward to Columbia River, and the Rocky Mountain or Plateau ground 

 squirrel (C. grammurus), which in California is known only on the east side 

 of the Mohave Desert, are closely related species. 



The life history, habits, food, distribution, etc., of the California ground 

 squirrel are described. It is stated that more than 3S7 of these squirrels 

 were found in California infected with bubonic plague during the past year. 

 The means of destruction are considered under the headings of trapping, poison- 

 ing, and fumigation. 



" In places where ground squirrels are abundant over considerable areas the 

 simplest, most effective, and least expensive way to destroy them is by the use 

 of grain poisoned with strychnin. Phosphorus and cyanid of potassium, 

 owing to the great danger attending their use, are not recommended, especially 

 since they are not more effective than strychnin." Coated grain, except during 

 the rainy season, gives far better results than soaked grain and kills the animals 

 more quickly so that they are much more likely to die above ground where 

 they can be seen. The formula perfected and recommended by the Biological 

 Survey, which consists of 20 qt. of clean barley, 1 oz. strychnia sulphate, 1 tea- 

 spoonful of saccharin, I teacupful of starch, and 1\ pt. of water, is prepared 

 in the following manner : " Dissolve the starch in a little cold water and add 

 1^ pt. of boiling water, making a rather thick solution. While hot, stir in the 

 strychnin and mix until free from lumps ; then add the sacchartu and beat 

 thoroughly. Now pour the poisoned starch over the barley and stir rapidly 

 until the poison is evenly distributed ; then allow the grain to dry. When dry 

 it will keep indefinitely without deterioration, . . . 



" The most economical method is first to use the starch-strychnin preparation, 

 and later to kill the few remaining animals by using bisulphid of carbon in the 

 burrows that are still occupied. The cost of barley coated with the starch- 

 strychnin preparation varies from about $4 to $4.75 per 100 lbs., . . . and 100 

 lbs. of the poisoned grain is sufficient to treat from 200 to 300 acres, according 

 to the abundance of the squirrels." 



Detailed directions for winter poisoning are also given. It is claimed that 

 the methods recommended are not dangerous to stock, but should not be prac- 

 ticed in places accessible to poultry. 



