June, 1917] Winter Observations of Muscid Flies 293 



Calliphora viridescens Desv. 

 This species was not found in the late autumn, but freshly 

 emerged specimens were taken in a meat trap on the 26th of 

 March. 



Cynomyia cadaverina Desv. 



This was among the first flies to appear this spring. It was 

 taken in the insectary on the 25th of February and outside on 

 the 20th of March, over decaying rabbit. The latest autumn 

 occurrence for this species in Columbus was on the 13th of 

 November, 191(3. 



Maggots taken on the 31st of January, 1917, from the earth 

 1^ feet from sheep manure pile were transferred to breeding 

 vials in the laboratory, where they pupated 4 days later (Feb- 

 ruary 4th) and an adult female issued from these on the 24th of 

 February. 



The immature stage again seems to be the hibernating 

 condition. 



Among the muscids collected early this spring and indicating 

 fresh emergence, as indicated by their clean, perfect condition 

 and comparatively soft chitin are Muscina stabulans Fall 

 (March 20th), Pseudopyrellia cornicina Fabr. (March 24) and 

 PoUeiiia rudis Fabr. 



Pollenia rudis Fabr. 

 The cluster fl}^ was found occurring as adults every now and 

 then throughout the winter. About 55 were taken December 

 4th, 1916, in the lock round-house at the Columbus Sewage 

 Disposal Plant. These flies were transferred alive to a breeding 

 cage in the cool chamber of the insectary. During sunny days 

 this chamber recorded from over 100 at noon to about 20 at 

 night. In the extreme temperatures thus provided, they were 

 quite active during sunlight, while toward evening they grad- 

 ually closed in towards a protected corner of the cage, where 

 they clustered until the sunshine warmed the atmosphere 

 again. They were given banana as food and a layer of wet 

 clay for possible oviposition. As soon as the females died 

 their ovaries w^ere examined for the condition of development. 

 These ovaries were immature, almost negligible until the last 

 female died on the 7th of March. Here the ova were about the 

 size of a normal egg of Musca domestica. All the ova in this 

 fly appeared to be about the same size. The longevity ranged 

 to more than 94 days. 



