AGRICULTURAL EXPERIMENT STATION. 



115 



mouth parts are constantly in motion during the process. But one egg 

 is laid in a place. 



Nature of the Reproductive System. 



We dissected several females and found the ovaries double. The 

 eggs giving the abdomen a swollen appearance and filling the abdo- 

 minal cavity. The egg masses consisted of about ten chains of eggs 

 on each side, each chain in about ten stages of development, making 

 the possible number of eggs the flies are capable of laying fully 200. 



The developmental stages are strikingly like those of Trypeta 

 pomonella, figured in our 1S89 Report, and as in that insect the egg 

 laying period must extend over considerable time. 



When Do the Flies Emerge. 

 Specimens kept in jars in a warm room began to emerge the last 

 week in April, but in nature were first noticed about June first. 

 They were mating at that date and punctures on the currants were 

 abundant indicating an earlier emergence than June 1st. The time 

 varies with the season and locality. No flies were seen in 1896 before 

 June 5th. 



How Long Do They Continue on the Wing. 

 Specimens were quite abundant about the first of June, were most 

 abundant from June 9th to 15th, and by June 25th more were to be 

 seen about the bushes. Making allowance for difference of time 

 of emergence the period of flight would not be over a month at the 

 lonarest. 



Fig. 7-a. 

 relative 

 ture and 



close to 



What Is the Nature of the Puncture. 



It is scarcely visible at first but soon be- 

 comes surrounded by a brown areola and 

 then is shown to be nearly circular and 

 about a half mm. in diameter. Extending 

 from it at one side is a narrow portion of 

 the epidermis from which the sub-epider- 

 mal cells have been removed by the ovi- 

 positor, giving it a semi-transparent ap- 

 pearance through which the egg can be 

 clearly seen close under the skin to one 

 side of the puncture. 

 This portion of the epidermis covering 

 the egg soon becomes whitish, opaque and 

 sunken. We were at a loss at first to 

 know how the egg could be deposited so 

 the skin at one side of the puncture but a study of the pro- 



Currant snowing the 

 position of the punc- 

 deposited egg. 



