36 



C. SASAKI. 



it, SO raising their Lody through a small distance. The space vacated 

 is no doubt soon filled up with the earth so that they can not descend 

 to their original position. They then contract the bladder and repeat 

 the operation, effecting another slight ascent. ]5y successive repeti- 

 tions of the same they finally gain the surface of the ground {I'l. Vf, 

 fig. 17 cl). 



The days in which the flies hatch cut beneath the ground are 

 always fair and bright with a temperature above 50° F. 1 hey appear 

 above the ground usually at from six to ten a. m. Those that appear 

 later in the day are comparatively few in number. On the other hand, 

 if the weather is rainy and the temperature below 50" F., they very 

 rarely make. their appearance. 



Generally on appearing above ground, they rest quietly for 30 

 to 40 minutes, after first crawling into some shady place if the rays 

 of the sun fall directly on the spot where they emerged. During 

 this time, their body deepens much in color and their folded wings 

 expand completely. When the wings attain their proper size, they 

 begin to vibrate tliem at short intervals and finally fly ofl" into the air. 



After a few weeks, they attain maturity, and deposit their eggs on 

 the under-surface of the leaves of the mulberry -trees to perpetuate their 

 offspring. The life history which we have been following is thus 

 completed. 



Measures for Protecting the Silkworm from the Ravages of the Fly. 



From the foregoing study of Ugimya sericaria, the following 

 measures for protecting the silkworm from the ravages of the fly sug- 

 gest themselves : — 



