Hugh Scott 107 



screened over with a wall of the white secretion, or in the few cases 

 where a larva has been seen to bore into an intact puparium, its entrance- 

 hole was covered in the same way (Perris, and ante, p. 10;")). The inner 

 surface of the puparium itself is not lined. 



In my experiments there seemed to be some preference of the larvae 

 for the more roomy blowfly-puparia, and beetles emerging from these 

 were on the whole larger than those which had pupated in puparia of 

 Musca domestica. No puparium was ever found to contain more than 

 one Necrobia. 



Other places besides empty puparia are used. Kemner (p. 200) cites 

 the observations made in the Danish Zoological Museum, where larvae 

 of N. ruficollis pupated not only in empty puparia of flies, but in cast 

 larval skins of Dermestes, closing them with the white secretion. Kemner 

 also quotes Lampert(i4) as recording the finding of larvae of N. ruficollis 

 in cork, the larval passages being closed with secretion : Kemner thinks 

 these larvae were probably piepaiing to pupate in the cork, just as did 

 those of Corynetes and Opilo kept in captivity by him. 



0]ie of my larvae pupated in a crevice in a piece of dried banana, 

 closing the opening with the white secretion. When nothing else was 

 available, or even in some cases where empty puparia of Musca were 

 available, the iVecrofem-larvae readily constructed cells in sawdust. 

 They plunged down into the sawdust provided for them in small vessels, 

 made winding burrows, and after a few days had excavated hollows, 

 nearly always in the angle formed by the bottom and sides of the 

 vessel. These hollows they lined with the white secretion, which held 

 the surrounding grains of sawdust together, thus forming a cocoon 

 which could be removed intact. Only the part of the wall of the cell 

 formed by the glass was left uncoated with sawdust or secretion, with 

 the result that the larvae and pupae could be seen within their pupal 

 cells. In these cells the larvae lie not fully extended, but slightly curved. 

 The excavation and lining of the cell appeared to take some time. 

 Occasionally larvae were seen in cells which they had not begun to line, 

 and once a larva was observed in a partly lined cell, with gaps in the 

 white coating, which were not filled in till the following day. 



Certain allied species make cocoons of the same type. Howard (ii) 

 describes Necrobia rufipes as forming papery cocoons, after boring into 

 the muscle of hams on the fat of which the larvae had been feeding, or 

 into neighbouring woodwork^. Mangan(i6) also describes and figures 



1 Compare Keuiner's account of the boring uf wood and cork by Opilu doincslicus and 



Corynetes. A larva of Dermestes which I placed in a small bottle in 1917, bored about half 



an inch into the cork, and pupated in the burrow. 



8—2 



