J. E. M. Mellor 6:i 



(size 1-2 lb.) and given a little of the manure in which they had been 

 found — when this material was very moist a little dry earth was added 

 to tempt them to pupate. 



Throughout the investigation it was found very difficult to overcome 

 the efforts of the larvae to migrate from the jars, in which they were 

 confined. A glass filter funnel was dropped into the mouth of each jar, 

 thus at once closing it and admitting air. However, in spite of this, 

 some larvae did either find a spot where some irregularity in the rim of 

 the jar permitted them to squeeze between it and the filter funnel, or 

 actually made their way up the inside of the funnel. Very few managed 

 this gymnastical feat, and the first path of escape was effectually blocked 

 later by a layer of plasticine. 



The temperatures recorded were taken with an ordinary centigrade 

 thermometer placed in a large glass tube, held in position by a piece of 

 cork, and surrounded at the bulb end by parafiin wax. The bulb end of 

 the glass tube was closed with a cork, the opposite end being left open. 

 This device, though prolonging the time necessary to leave the ther- 

 mometer in the manure, enabled the temperature to be read before the 

 mercury fell on the withdrawal of the tube from the heap. 



A table giving the species found in the larval or pupal stages, from 

 which adults were actually bred, is given ; those which are additional to 

 Graham-Smith's (1916) list being marked; the kind of manure in which 

 each species was found, the dates of findings and the sexes, which 

 emerged, are also shown (pp. 64, 65). 



Summary of observations. 



1. Thirty-nine species were actually bred from larvae or pupae found 

 in natural situations during the winter; 31 of these are additional to 

 Graham-Smith's (1916) Hst. 



2. Larvae of DoUchopodidas were found in soil near cow manure, and 

 were identified by Dr D. Keilin, but were not successfully reared. 



3. Pupae of Musca domestica were found during winter in horse 

 manure but the adult was not reared. 



4. It is possible that larvae and pupae of other species were found, 

 though they were not successfully reared. 



5. The distribution of dipterous larvae in a manure heap in winter, in 

 the Eastern Counties, is extremely local. Similar observations were made 

 at Dallas and at Uvalde, Texas, by Bishopp, Dove and Parman (1915), 

 but they do not state whether their observations referred to both summer 

 and winter, or to either period in particular. 



