288 The Ohio Journal of Science [Vol. XVII, No. 8, 



placed in a breeding box in the insectary where one male Musca 

 domestica L. emerged March 10th, 1917 (13 days after isolation), 

 another male March 11, 1917 (14 days) and two females on 

 March 12th (15 days). These evidently spent most of the 

 winter in this resting stage. The remaining puparia of this 

 mass revealed a large percentage empty and showing the 

 evidence of emerged parasites. Of 615 housefly puparia 

 (identified by the structures of the posterior stigmal plates as 

 seen under the binocular) 196 were so injured that I could not 

 tell what had emerged from them. Of the more perfect 419 

 puparia, 385 or 91.8% had small holes characteristic of para- 

 sitized pupae and 34 or 8.1% had the normal T breaks at the 

 anterior end. 



Briefly, then the above hibernating experiments and observa- 

 tions with Musca domestica L. may be summarized for Mary- 

 land and Ohio as follows: 



1. All stages may be obtained in rare conditions of artificial 

 heat and breeding media. 



2. Under natural conditions neither eggs nor maggots were 

 found alive in the normally perferred situations, although 

 the maggots will probably be found in early winter. 



3. The adults did not live more than 44 days (experi- 

 mentally) nor were they collected during the winter proper in 

 houses where it was formerly supposed they were hiding. 



4. The few samples of puparia taken from their preferred 

 environment in midwinter (February 26th, 1917) at Columbus 

 and then their successful emergence March 10th to 12th under 

 artificially heated conditions, in spite of the large number 

 affected by fall parasites, apparently indicates that under 

 natural conditions the housefly (Musca domestica L.) hiber- 

 nates as pup^. 



The winter of 1916-17 afforded an unusually good oppor- 

 tunity to study hibernating conditions because the temperature 

 seemed to lower gradually at first and the cold part of the season 

 was not interrupted very frequently by unusual warm periods. 

 However, such interruption did occur about the 6th of January 

 and again on the 26th of February. 



Lucilia sericata Meig. 

 The common greenbottle was collected outside on the 7th 

 of November, 1916, and was not taken again until the 24th of 

 March, 1917. 



