Apr. 15, 1918 



Overwintering of the House Fly 



165 



are not normally found in horse manure, but were doubtless introduced 

 in the pig-manure-bran mixture. 



Table V. — Niimber and species of flies emerged during the spring of igi6 from six heaps 

 of overwintered horse and pig mamire 



Species. 



Muscina assimilis 



Muscina stabulans 



Fannia canicularis Linnaeus. . . 



Hydroiaea houghi Malloch 



Ophyra leticostoma Wiedemann 



Phorbia sp 



Scatophaga furcaia Say 



Syritta pipicns Linnaeus 



Sarcophagidae 



Total 

 number of 



flies 

 emerged. 



Period of emergence. 



May 4 to 20. 

 May 4. 



April 6 to May 22. 

 April 24 to May 31 

 April 28 to May 31 

 April 28 to May 4. 

 April 6 to May 6. 

 May 6 to 22. 

 May 2 to 29. 



Three experiments were carried out during the winter of 191 6-1 7. 

 They were started on October 3, 191 6, by placing in each of three wooden 

 frames 8 bushels of fresh horse manure containing little straw and seen 

 to be quite heavily infested with larvae of both Musca domestica and Stom- 

 oxys calcitrans. Additions of horse manure were made from time to time 

 up to January 8, 191 7, when each heap contained 40 bushels of manure. 

 Larvae of Musca domestica and Stomoxys calcitrans were seen in all manure 

 added to the heaps up to and including that of October 24, all additions 

 after this date appearing to be free from infestation. 



The first of these three experiments was managed somewhat differ- 

 ently from the others. On October 9, 191 6, i quart of moist bran con- 

 taining hundreds of house-fiy larvae was put on the heap. Again on 

 three occasions — December 27, 1916, and January 4 and 10, 1917 — 

 2 quarts of moist bran which had been previously exposed in the animal 

 house and was heavily infested with fly larv^se were buried in the heap. 

 In this way fully 2,500 house-fly larv^ae were added to the normal infes- 

 tation of the manure. The pyramidal cover, with attached flytrap, was 

 put in place on November 13. From this date to December 11 the fol- 

 lowing species were taken from the trap : 



Musca domestica 20 



Stomoxys calcitrans 247 



Fannia canicularis i 



Scatophaga stercoraria 2 



No further emergence was noted during the winter until March 22, 

 1917. The trap was regularly emptied from that time until June 4, the 

 catches being summed up in Table VI. 



41813°— 18 2 



