76 DECIDUOUS FRUIT INSECTS AND INSECTICIDES. 



Egg laying had begun only sparingly on March 21, but by the 

 afternoon of March 23 many eggs could be found. A thorough 

 search in three different orchards failed to show any larvae. Oppo- 

 sition was at its height about March 23 to 30, and was practically 

 over by April 5, the adults having mostly disappeared by this time. 

 The females seem to die off in advance of the males, showing about 

 the same comparative difference as was the case at the beginning of 

 the emergence. On April 3 and 4 as high as eight males to one 

 female were noted. On April 6, two orchards were closely examined, 

 and while many males were in evidence not one female could be 

 found. 



THE EGG. 



Egg laying began in 1910 about March 16, just as the Black 

 Tartarian cherries were beginning to open first blossoms. The females 

 oviposit quite freely in the orchards, always on blossoms just about 

 ready to spread the petals. (See PL X, fig. 1.) The greater number 

 of eggs are deposited in the sepals of the flower, although some are 

 deposited in the upper portion of the calyx cup, but only in rare cases 

 are any eggs deposited below the middle of the calyx cup. The female 

 inserts her ovipositor in the tissue, usually from the outside, making, 

 for the size of the insect, a rather large, deep incision and placing the 

 egg in the opening just made. The egg is usually placed at such 

 depth that it can be seen from the opposite side of the sepal. 



The egg (fig. 23, a) is 0.5 mm. long by 0.3 mm. wide, whitish, 

 slightly shiny, and somewhat kidney-shaped. 



Incubation. — Of a total of 35 eggs deposited between 8 a. m. March 

 21 and 8 a. m. March 22, 27 had hatched by 8 a. m. March 25, the others 

 hatching during the day. Another batch of four eggs, deposited 

 March 25, hatched March 30. There were three other observations 

 in which the eggs hatched in five days after oviposition. Mr. Braucher 

 reports another instance of eggs that were deposited on March 28 

 hatching in the afternoon of March 3 1 . The summary of these records 

 together with many field observations shows the length of time re- 

 quired for incubation to vary from three to six days, averaging from 

 four to five days. This time is influenced by temperature conditions, 

 as eggs kept indoors required from 18 to 36 hours longer than eggs 

 kept outside. The time of hatching coincides very closely with the 

 falling of the petals from the blossoms of the variety attacked. 

 Usually the eggs are deposited at or just prior to the opening of the 

 petals and hatch with the falling of the petals. One very interesting 

 observation was that the adults invariably deposit their eggs at this 

 stage of blossom development regardless of the variety. In one 



