1916 ENTOMOLOGICAL SOCIETY. 137 



Erom this table 3, we find that flies were active up till as late as October 32nd ; 

 having since September 1st deposited 1,739 eggs on six cauliflower plants. The 

 egg deposition on six cabbages for the month of September was 95.5, while the 

 deposition on a like number of cauliflowers over the same period was 1,311. This 

 indicates the importance of pursuing the life history on more kinds of plants than 

 one. The records from cabbages alone would incline towards an entirely different 

 rendering of the actual situation. 



(See chart covering egg deposition on six cauliflowers.) 



Autumn Larval Notes. 



We are now satisfied, in the first place, that flies freely emerge from the soil 

 in September, and in the second place that quantities of eggs are laid around 

 plants until late into October. The high egg fertility percentage is maintained 

 throughout the entire year, consequently we are justified in assuming that larval 

 forms may be found working on the roots of plants during November and December. 

 This assumption is supported by fact inasmuch as larvae, freshly hatched, from 

 late September eggs, having been placed on plants in pots, developed to 2 mm., 

 3 mm., and 4 mm. in length by the commencement of November. Inasmuch as 

 these pots were sunk in the soil out of doors, we claim with assurance that the con- 

 ditions were precisely natural. 



Eggs taken from plants in the field between September 13th-26th, were hatched 

 in the laboratory and placed on the soil around a potted plant (which was in turn 

 sunk in the open soil), developed maggots 3 mm.-4 mm. long by October 25th. 

 Larvae hatching after September 26th and before 30th, treated in the same way 

 developed maggotsi 2 mm. long by the close of October. There is no question of 

 doubt that the larvse found in both these instances would mature, pupate and pass 

 the winter. It is true that no further notes were taken on them after this date, 

 but their general thrifty appearance does not allow of much doubt that they will 

 survive. Eggs hatching in October were also placed around the stems of plants 

 and they developed slowly during the early days of November. Frost, it would 

 seem, might affect them, especially the very small larvae. Given no severe weather 

 in November and December, there is, again, little doubt that October eggs will 

 persevere also to puparia by the approach of winter. Real winter weather seldom 

 sets in with any degree of permanence in this locality until the New Year. 



10 E.S. 



