Insect and Disease Control 241 



Potassium cyanide taken internally is one of the most 

 deadly poisons known. Hydrocyanic acid gas, if inhaled, 

 is no less destructive of life. Hence, in handling the chem- 

 icals and in all details relating to the generation of the gas, 

 the strictest precautions against accidents must be taken. 



White peachrscale, or West Indian peachrscale (Aulacaspis 

 pentagona) 



Owing to its general occurrence in the West Indies, this 

 insect was at one time supposed to be native there, hence 

 its name. It is now known, however, to be widely distrib- 

 uted in many parts of the world. 



Appearance. 



A full-grown female scale is about -j^ inch in diameter, 

 dirty white in color and nearly circular in outline. The 

 scale-covering of the male is elongated and whiter in color 

 than that of the female. 



Distribution. 



Though probably not occurring in a large number of 

 commercial peach districts in the United States, this insect 

 is widely distributed from the District of Columbia south- 

 ward. Its range westward does not appear to have been 

 recorded. 



Life history and habits. 



The winter is passed in the mature form. In the lati- 

 tude of Washington, egg-laying begins about the first of 

 May. The eggs hatch in a few days, the young soon settle 

 down, the protective covering is developed, and by the middle 



