36 



THE BEPOET OF THE 



No. 36 



Habits of Immature Forms: The larvse and nymphs feed principally on the 

 lower surface of the leaf, generally close to the veins. They may remain feeding in 

 one spot for several hours. 



Each moult is preceded by a quiescent period of one or two days during 

 which time the larva or nymph remains attached to the leaf and shows indica- 

 tion of life. 



Length of Larval-nymphal Period: In our studies this period varied from 

 17 days in the spring to 7 days in June and July, the average being 10.7 days. 

 Puller data covering the six generations are shown in Table No. 3. 



(a) Felleniburg plum severely injured by 

 mite. (Reduced) 



TABLE No. 3 — Showing Duration of Larval-nymphal Period 





No. of 

 Exp's 



No. of 

 Nymphs 



Time of year. 



Nymphal Period 



Temperature 



Brood 



Min. 



Max. 



Aver. 



Min. 



Max. 



Mean 





Days 



Days 



Days 





1st 



11 



48 



May 3rd. to May 21*t 



16 



18 



17 



34 



75 



53 



2nd 



12 



60 



June 5th to June 20th 



8 



11 



9 



42 



87 



64 



3rd 



13 



72 



June 20th to July 13th 



7 



10 



8 



48 



98 



77 



4th 



12 



82 



July 18th to Aug. 3rd 



7 



10 



9 



52 



91 



76 



5th 



15 



58 



Aug. 7th to Sept. 29th 



8 



13 



11 



46 



86 



66 



6th 



13 



35 



Sept, 1st to Sept. 23rd 



11 



15 



13 



48 



90 



66 



