198 PROCEEDINGS ENTOMOLOGICAL SOCIETY 



He found only one generation per annum, but admits the 

 bility of the existence of a summer generation. 



To our knowledge, the larvae of Pollenia rud'is has not been 

 recognized in this country until found by the senior author dur- 

 ing June 1916'. We have been able to verify many points made 

 by Keilin, but find that the life history of this fly in Washington is 

 in many ways quite different from that found by Keilin in Paris. 



In the first place, worms, identified as Allolobophora chlorotica, 

 were collected in many places near Washington and several widely 

 separated places in the United States during October, November 

 and December, 1915. These were examined by Dr. Townsend, 

 Mr. Kisliuk, and by the writers, but no infested worms Avere 

 found during that period. In the Spring of 1916 no infested 

 worms were found during April, although collections and exami- 

 nations were made from time to time. The first infested worms 

 Avere found among a lot collected in the field June 15. 



On June 12, 1916, Pollenia caught in traps baited with banana 

 Avere put in breeding cages and supplied Avith moist earth and 

 banana for food. Eggs Avere found on the soil June 19, and AVC 

 have had no trouble, during the summer in obtaining fertile eggs 

 from flies caught in traps. Isolated pairs of Pollenia (bred 

 specimens) failed to oviposit, so that the preoviposition period 

 has not been determined and the number of eggs laid by each 

 female is unknoAvn. The eggs are laid singly, partly hidden in 

 cracks in the soil. Our records shoAV that they hatch about three 

 days after deposition during the summer. 



The first stage larvae of Pollenia are very active and seem to 

 be able to penetrate the Avorm at almost any point in the body 

 wall. The point of entrance is not limited to the male genital 

 opening, or to any natural orifice. In Avorms on Avhich larvae 

 were placed by us, Ave found them entering the seventieth, sixty- 

 fourth, fiftieth and thirty-fifth segments. Infested Avorms col- 

 lected in the field have also shoAvn cases Avhere the larvae haA r e 

 entered segments far back of the clitellar regions. 



We have found no indications of a dormant period during Avhich 

 the larvae remained practically motionless in the body cavity 

 of the Avorni. Of course, AA r e have been Avorking Avith summer 

 generations, but our examinations during the Fall of 1915 and 

 Spring of 1916 failed to shoAV any over Avintering forms of thr 

 larvae. 



Our records of summer generations indicate the folknving de- 

 velopmental periods. 



Egg stage 3 d;iy > 



Larvae stages 13 to 22 days 



Pupal stages 11 to 14 days 



Total developiiionltil period 27 to 39 days 



