THE MONTHLY BULLETIN. 



191 



the durtitioti oi' tlu'se vnryirif; from tliroe to ten days. The time 

 oeeupiecl from the first hatched n\ inph to the adult averages about 

 thirty days. 



In Sacramento liic broods are continuous throughout the year, all 

 stages of Ihe insect being present. During January the death rate of 

 the newly hatched young was high, about one-half dying, this probably 

 being caused by the unusually cold weather. 



CONTROL. 



A strong stream of water played on the infested plants that were 

 under observation sufficed to destroy the insects. If this can not 

 readily be done, spraying mnst be resorted to. On tender ornamentals, 



Fig. 64. — Nymphs showing the comparative 

 size of tlie different instars. Greatly enlarged. 

 (Original.) 



Black Leaf 40, at a strength of 1 to 1.500, is recommended. On hardy, 

 resistant plants kerosene emulsion can safely be used. For this i)ur- 

 pose a stock solution of one part of kerosene to two parts of water 

 should be used at the rate of one gallon of the emulsion to twenty 

 gallons of water. 



