THE CITRUS MEALY BUG 



299 



"A careful incasurcnieiit with a micromillimeter gives tlie following re- 

 sults: joints 1, 2, 3, 4, 5, 6, 7, 8; 96, 88, 96, 68, 80, 81. 44, 104." 



"The formula of Comstock's measurements with the eye 8, 3, (2, 7 j, (6, 5), 

 4 omitting joint 1 ; of these by myself with the eye 8, 3, (1, 2), 5, 4, (6, 7), 

 and with the micromillimeter 8, ( 1, 3), 2, 6, 5, 4, 7. This, I believe, is the 

 first time that tlie true measurements of the antennal joints of Dactylopiiis 

 citn have been given." From all of the above it is readily seen that there 

 must be a large degree of variation in the antennal articles of different in- 

 dividuals. The mounting, and tlie position of the insect uj^n the slide, no 



Figure 116. Egg Masses of Pseudococcus citri on Lemon. 

 (Pom. .louni. lOnt. Vul. 1, No. 2, Fig. 18.) 



doubt, plays a very important part in these determinations. For general 

 work the eye measurements ( taken by the eye through a microscope ) must 

 ])C used by the average student for ready reference. In combining all of the 

 formulse of eye measurements we may fix a more exact formula as follows : 

 &, 3, (1, 2. 7), (5. 6), 4. Tlie combined number of antennal articles equals 

 about one-ninth the length of the insect's body. 



Roslruiii — Short, stout, and in two distinct divisions, the basal division 

 being much broader than the apical. The rostral loop is nearh- half as lung 

 as the body. 



