86 BULLETIN 351, IT. S. DEPARTMENT OF AGEICULTURE. 



scales, can best be determined by displacing a number of scales daily 

 during the early part of June. In tbe region of Mont Alto, Pa., 

 the yomig will appear under the scales about June 12. For this 

 coatmg spray use the following formula: 



Pounds. 



Stone lime 15 



Sulpluir 20 



Flour 10 



Water to make 50 gallons. 



The lime and sulphur are combined exactly aB in making self -boiled 

 lime-sulphur. The flour is made into a thin batter with cold water 

 and cooked to a paste. It is then added to the lime-sulphur, and the 

 whole should then be diluted to 50 gallons, when it is ready for use. 

 Particular care must be taken to get a batter free from lumps; if this 

 is done, and the spray is strained through a sieve, there will be no 

 trouble in passing it thi'ough the nozzles. This spray when properly 

 applied will kiU from 94 to 100 per cent of the larvae. It is effective 

 only against the leafward migrating larvae and is useless if applied 

 after the larvae have attached to the leaves. 



SUMMARY. 



SUMMARY OF LIFE HISTORY. 



Tlio female of the terrapin scale reaches maturity about the 1st of 

 June and gives birth to living young soon afterwards. These are 

 retained for a period of from 1 to 3 days in the brood" chamber, which 

 is a dome-shaped cavity beneath the scale. They then emerge and 

 migrate at once to the underside of the leaves, where they settle, 

 mostly along the midrib and the larger veins. The first instar, which 

 lasts about 18 days, is vegetative and the larvae show no sexual differ- 

 entiation, but during the second instar, which also lasts about 18 

 days, sexual differentiation is very pronounced. At the end of this 

 instar the female is. very flat and circular, while the male, which is flat 

 and decidedly oval, is protected by a conspicuous waxy structure 

 called the puparium. After the second instar the sexes follow 

 entirely different lines of development. 



The female remains for 1 day upon the leaves after entering the 

 third instar, which is the final instar for this sex. Duiing this day it 

 secretes a thin wax scale, which protects it during the twigward 

 migration. At the beginning of this migration the female larvae 

 abandon the leaves and pass to the basal part of the new gi'owth, 

 where they make their final attachment within the area of greatest 

 illumination. They then commence a period of rapid growth, during 

 the first 1 1 days of wliich they develop their mating color, which is a 

 conspicuous red band upon the middorsal line. At the time the 

 dorsal band is completed the male migrates to the leaves, mates, and 



