314 POMONA COLLEGE JOURNAL OF ENTOMOLOGY 



may finally do so. The liability to lose all of her offspring is very slight, 

 under common methods of orchard practice. 



If the food supply is merely reduced by drying out of the fruit, the 

 rate of reproduction is more rapid than under the more adverse conditions, 

 for there is more vitality displayed in all broods. The following interesting 

 experiment was carried out in the laboratory. 



In a glass jar was placed a lemon, taken from a tree which had just 

 been fumigated (Oct. 7, 1909). There were eight living individuals, all of 

 which appeared to be but half-grown. The jar was labeled and set away 

 in a perfectly dry place to prevent the rotting of the fruit. No apparent 

 changes were evident until the lemon began to dry and shrivel, and then 

 egg-laying began rapidly. Within a short time scores of young began to 

 appear. This continued until at least three distinct broods appeared. On 

 January 19, 1910, the accompanying photo (Fig. 119) was taken. In order 

 to make the necessary enlargement, only half of the lemon could be photo- 

 graphed, but it shows well the conditions three months after the lemon was 

 placed in the jar. Still more appeared until the rind became perfectly dry, 

 when the younger forms began to die. All forms were not dead until March 

 1st, 1910. This shows what might be expected from a single infested orange 

 or lemon that might be dropped into a clean orchard. 



Heat. — During the dry, hot months, of the late summer, the mealy bugs 

 are less in evidence than at any other season. This seems to show that the 

 hot weather has something to do with the retarded development so in evidence. 

 There is no doubt but that the insect prefers the damp, even climate of the 

 coast sections to the hot dry interior valleys, but even in the hottest climates 

 the pest thrives remarkably well. In the interior citrus districts of California 

 and in Arizona it is always a menace. While there is no exact method of 

 ascertaining just how much heat the insect can thrive under, the following 

 tests may serve to show the heat death line to some degree. These hot-water 

 tests were made to find out at what temperature, water, into which boxes, 

 infected with the eggs, larvae, and adult mealy bugs, were dipped, must be 

 maintained to insure the extermination of all life. 



BqiiipHiciit. — A fifty gallon iron kettle surrounded by a brick wall, con- 

 taining 30 gallons of water. Heated by a wood fire at the bottom. A 

 thermometer for ascertaining the temperature of boiling liquids. 



A wooden box with a fine wire-sieve bottom was used as a container for 

 dipping infected fruit, leaves, and twigs. 



The best samples of infected fruit possible were obtained for the experi- 

 ments. A large number of egg-masses, larv;e, and adults infected each of the 

 many samples used at a dipping. 



