HEMIPTERA. Ill 



insects which should be neglected, the rapidity with 

 which they breed, and the difficulty of killing all the 

 individuals of any one brood, making them exceedingly 

 hard to get rid of. The females of many of the scale 

 insects in the adult stage secrete about themselves an 

 impervious shell of waxy scales or a covering made of 

 the juice of the wounded plant whose stems are furnishing 

 them with food. These coverings increase the difficulty 

 of treatment at this stage. 



For infested plants in the green-house, or even for 

 trees in the nursery, fumigation with hydrocyanic acid 

 is recommended by those who have tried it. It certainly 

 kills all individuals that have hatched from the egg. 

 In the fumigation, a cloth covering large enough to 

 envelop the plant or the tree is necessary. The fumigant 

 is made by pouring water into commercial sulphuric acid 

 and adding cyanid, of potassium; the three substances 

 to be in the proportion of ten ouncps of the water to one 

 ounce of the sulphuric acid to three ounces of potassium 

 cyanid, made up in the quantity required, the amount 

 given being sufficient to fumigate one hundred cubic feet 

 of space. Dilute sulphuric acid, which is usually 

 made up in the proportion of one to ten, if it can be 

 bought, is better to use than to attempt the making of 

 the mixture one's self. There is always a little danger 

 attending the rapid mixture of sulphuric acid and water. 

 If you make the mixture, take the precaution to pour 

 the water in slowly. The fumes of the mixture acting 

 on the cyanid of potassium are deadly poison; hence 

 care must be taken not to breathe them ; they are intended 

 only for the scale insects ! Have all other things in place 

 before you pour the mixture on the potassium cyanid. 



The division of the true bugs, or the Heteroptera, 



