264 MAINS AGRICULTURAL EXPERIMENT STATION. 1907. 



Orchard Tent Caterpillar. 



The large percentage of dead eggs of the common orchard 

 tent caterpillar, C. americana, was noticed this season by even 

 casual observers. This species was exceedingly numerous dur- 

 ing 1906 and in certain Orono orchards as many as 5 to 20 

 egg clusters to a tree were found in the spring. 



Following is the hatching record of 24 egg masses collected 

 in April before any eggs had hatched : 



Egg mass No. 



Eggs 



Egg mass No. 



Fggs 



Egg mass No 



Eggs 





Hatching. 





Hatching. 





Hatching. 



1 







9 







17 



41 



2 







10 







18 



138 



3 







11 



92 



19 



4 



4 







12 



93 



20 



96 



5 







13 







21 



108 



6 







14 



64 



22 







7 







15 



133 



23 



5 



8 







16 



26 



24 



134 



This gives a total of 927 caterpillars to 24 egg masses, a 

 number which would ordinarily be equaled by 4 or 5 egg 

 masses. 



The peculiar weather of the past winter may perhaps be 

 held accountable for a share in this condition, not so much 

 because of the excessive cold but because of the sudden changes 

 occurring. On Jan. 16 the temperature swung from a maxi- 

 mum of 21 degrees above zero to a minimum of 40 degrees 

 below zero the following night, making a range of 61 degrees 

 in less than 24 hours. Jan. 21 the temperature ranged from 

 47 degrees above zero to 13 degrees below. It seems probable 

 that a winter unusually long and severe with sudden fluctuations 

 in temperature would be perilous for insect eggs exposed upon 

 the twigs of trees as are those of the tent caterpillar. 



Cherry-Tree Tortrix, Ar chips (Caccecia) cerasivorana. 



The "ugly nests" filled with little yellowish, black-headed 

 caterpillars have been very numerous for several seasons, on 

 wild cherry for the most part, though sometimes on apple and 

 raspberry. One colony just hatching from the eggs was col- 

 lected at Portland June 20 on chokecherry. These were reared 

 in the insectary on apple leaves. The moths which developed 

 from this colony had mostly emerged by August 6. A colony 



