THE CITRUS MEALY BUG 307 



THIRD NYMPHAL STAGE. 



The secoiul moult occurs, ou the average, about 15 days after the first. 



The antennae now consist of eight segments, and are 0.264 mm. in length. 

 The basal segment is quadrangular in outline, and the eighth is nearly as long 

 as the three preceding taken together. The character and the number of the 

 antenna! segments readily distinguish this stage from the preceding ones, 

 Imt are absolutely of no value in separating it from the mature or last stage. 

 In other characters they do not differ materially from those of the preceding 

 stages. 



As all previous workers have considered the antennae in the first nymphal 

 stage as consisting of only six segments, I would like to draw attention to the 

 fact tliat in all specimens which I have examined there were seven clearly- 

 defined segments in the first and second nymphal stages and eight in the third, 

 as well as in the adult female. 



ADULT FEMALE. 



The third and last moult takes place, on the average, about 13 days after 

 the second. I found it very difficult to secure many observations on the exact 

 time of this moult on account of the roving habits of the nymphs under 

 observation. 



.\fter this moult the females do not usually move about, but remain 

 practically motionless. Egg-laying commences in from 15 to 20 days later, 

 and continues from 10 to 14 days. An interesting observation worth recording 

 is that the females are usually not of a uniform size at the time when they 

 commence egg-laying. This has been pointed out by Reed in his thesis, and 

 I had many opportunities of verifying his observations. Often what I, judg- 

 ing from the size only, considered were nymphs in the third stage would 

 prove to be mature females and commence egg-laying. 



To the preceding accounts may be added the following orchard observa- 

 tions taken at Santa Paula, Ventura County, California, during the years 

 1909 and 1910: 



EGGS AT SANTA PAULA. 



The egg-laying in the field certainly differs from that seen in the labora- 

 tory where the temperature is more uniform. It covers a period from two 

 weeks to one month. For breeding material, I keep infested fruit on damp 

 sand and under such conditions the egg-laying usually requires but two 

 weeks. On fruit placed in jars, where it soon begins to wither, the egg-laying 

 may occupy but 10 days or even less, while mealy bugs placed in boxes, 

 jars, or cells without food, deposit most of the eggs in one week. Under 

 extreme unfavorable conditions, such as excessive heat and dryness, the eggs 

 are laid in the course of three days. The conditions of egg-laying also 

 influence the time for hatching, lender the most favorable conditions the 

 eggs first laid begin to hatch about the time, or a little before, the last eggs 

 are deposited. This accounts for the great difference in the sizes of the in- 

 dividuals from the same brood. Conditions also influence the number of 



