200 Maine Agricultural Experiment Station. 1917. 



TABLE 10. 



Dates of First and Last Emergence of Adults With Different 



Soils. 



Dates, first and 





i 



Bush in shade 



last emergence 



Kind of soil 



Kind of fruit 



or sunshine 



May 22— Jime 18 



Loose soil covered 

 with manure 



Red currant 



Sunshine 



May 30— June 14 



Loose soil covered 

 with manure 



White currant 



Sunshine 



May 27— June 13 



Loose soil covered 

 with manure 



White currant 



Sunshine 



May 25— June 12 



Loose soil covered 

 with manure 



Gooseberry 



Sunshine 



May 22— June 5 



Loose soil 



Red currant 



Sunshine 



May 27— June 2 



Soil covered with 

 coal and wood 



ashes 



Whits currant 



Sunshine 



May 25 — June 9 



Sod 



Red currant 



Sunshine 



May 27— June 4 



Sod 



Red currant 



Partial shade 



May 31 — Jime 5 



Clay 



Red currant 



Shade 



If the dates of emergence of the adults are compared in the 

 cases where loose soil was covered with manure, it is evident 

 that there is a difference of 3-8 days between the first issuance 

 of the flies and 1-6 days between the last emergence. The maxi- 

 mum emergence occurred on May 31-June 2, in each instance. 

 The records were obtained in the same garden, the cages were 

 within a few feet of one another and the kind of soil, conditions 

 of moisture and sunshine were apparently the same. It may 

 be possible that from puparia which are near the surface of the 

 ground the flies issue first while from those deeper in the soil 

 the trypetids emerge later in the season. Again, early and late 

 maturing larvae may have some effect on the duration of the 

 pupal period. Data on such factors are necessary before definite 

 conclusions can be drawn. 



Sexual Maturity. 



Of 35 trypetids which issued on May 20, one pair was 

 observed in copula (Fig. 17, E) on May 30, 10 days after emer- 

 gence under laboratory conditions. To determine how soon 

 mating takes place under natural conditions, currant fruit flies 

 were marked by amputating part of a leg and then set free in 

 a currant and gooseberry garden. A specimen which issued on 

 June 3, was marked and liberated on the same day and was taken 



