A NOTE ON THE HIBERNATION OF FLIES 83 



on the second floor seems to have been the site of the densest 

 swarm, which at its maximum not only covered the bay- 

 window but formed an elongate mass on the south and west 

 ceiling, which was described to me as resembling a thick coil 

 of black rope some three inches in thickness. 



All the evidence seems to indicate that the specimens of 

 Liintiophora septemnotata entered the house in autumn to find 

 quarters in which to pass the winter. It will be observed 

 that all the specimens are female ; no doubt the males died 

 off at the end of autumn. 



I have made a careful examination of the internal organs 

 of ten specimens of L. scptcmnotata taken at random from 

 the two batches collected. The specimens varied in length 

 from 4 to 4-7 mm. All proved to be impregnated, their 

 three receptacula seminis (spermothecae) being crammed 

 with long filamentous spermatozoa, which, when liberated by 

 rupture of the receptacula, exhibited the characteristic lashing 

 movements. Each ovary is a small oval mass (the shorter 

 diameter is about -4 mm.), in which the short and very 

 immature ovarian tubes can be distinguished. The ovary 

 forms a striking feature of the dissection, owing to its tracheal 

 supply being disproportionately large at this stage. The 

 mid-gut is empty in every case, but the hind gut contains 

 opaque granules evidently of excretory origin, as similar 

 granules are present in the Malpighian tubes. Between the 

 alimentary canal and the body-wall is a large fat-body.^ 



Examination of the organs shows that the females are 

 impregnated, and that, therefore, on the return of suitable 

 conditions, those females which survive the winter could 

 emerge from their winter quarters, feed, mature their ovaries, 



^ One female Miiscina stabulans was dissected, and presented similar 

 conditions, a mass of living sperms filling each receptaculum seminis. 

 One female Calliphora grcenlandica was also dissected, and its recepta- 

 cula carefully examined, but spermatozoa were not present. Its other 

 internal organs were in a condition similar to those of the LimnopJwra 

 described above. Perhaps this specimen of C. grcenlandica emerged 

 late from the puparium, i.e. in late autumn, when males were scarce or 

 had died out, and had thus not been impregnated. This species does 

 not appear to be common around Edinburgh, so that there might be a 

 considerable chance in autumn against a female being impregnated. 



