[ 166 ] 



Unfortunately, there is no evidence in the paper regarding the locality to 

 which the data relate, but it would appear that the species may exist in the 

 pupal condition from October to April. 



For comparative purposes we append our data, which show that we are 

 familiar with the life cycle of the parasite during the period from February 

 to August, and that our information would indicate that the winter is spent 

 in the larval condition in our area. Both records agree in showing that two 

 generations occur in the year — a short-lived summer and a longer winter 

 generation. 



April — May June July Aug. Sept. Oct. — Nov. Feb. March April 

 Bucentes geniculata P.I. I.L. L.P.I. I. ? ? ?L. L. L.P. 



Pupation. 



Observations show that usually the maggot leaves the body of its host 

 and pupation takes place .outside in the soil. After having emerged from the 

 host larva, the parasitic maggot may still remain attached, as described later, 

 to the tracheal trunk of the host, but usually the separation from the host, 

 preparatory to pupation, is complete. In one instance, however, pupation 

 was observed to have taken place within the host larva — the latter being still 

 alive. 



Within twenty-four hours after the maggot leaves its host, pupation is 

 complete. 



Period of Pupation. 



First generation. In the season 1918, pupation was first observed on 

 April 1st. The earliest date on which Bucentes flies emerged was April 23rd, 

 so that approximately pupation extends over a period of three weeks. 



In the season 1919 puparia were first observed on April 24th and flies 

 began to emerge on May 14th. In this instance, the duration of pupation was 

 20 days. 



Second generation. From observations made on pupae obtained from larvae 

 of the second generation in the season 1919, we found pupation to extend 

 from July 8th to 25th, i.e. over a period of 17 days. 



Emergence of Adults. 



In 1918 adult Bucentes flies were seen in the observation cage as early as 

 April 23rd. Emergence continued until June 4th, after which date all the 

 flies had died off. 



In 1919, when the weather was less favourable, no flies were seen until 

 May 14th. By June 13th all the flies had died. 



In 1918, emergence continued therefore over a period of about six weeks. 

 The flies which issued in April were rather small, but those which emerged 

 during May were normal in size. 



In 1919, emergence of flies continued only for about four weeks. In the 



