108 Biolofiji of Necrobia ruficollis 



cocoons formed by this species in bales of cotton. Information about 

 N. rufipes, with small figures of its larva, pupa, and cocoon, is also 

 given by Riley (2i) and Smith (23). Kemner records that a larva of 

 Necrobia violacea made itself a hollow in the cotton-wool stopper of the 

 tube in which it was imprisoned, used its secretion also, and pupated in 

 the cell thus formed. Perris writes of Coryneies coeruleus ( = rufcornis) 

 lining its pupal cells with white secretion: and Kemner describes how a 

 larva of the same species, in captivity, excavated itself a hollow in the 

 cork of the vessel, and lined the hollow with shining white material. 



Though I once watched a larva, through the side of a glass vessel, 

 turning about in its partly lined cell, and working over the walls with 

 its mouth, I could not see whether the secretion was being actually 

 produced from the mouth, and have found no decisive statement in the 

 literature as to how it is produced^. 



Heeger gives 12-14 days as the duration of the pupal stage. My 

 somewhat incomplete data indicate about 20 days as the period from the 

 making of the cocoon to the emergence of the adult. This was at rather 

 lower temperatures than those mentioned on p. 102, since I kept the 

 vessels in which the larvae pupated in a room less strongly heated than 

 the fly-room. But the larva may not become a pupa immediately after 

 the completion of its cell, and the adult after its transformation remains 

 in its cell for some time (a matter of days in some cases) before emerging ; 

 this could be seen, in the sawdust-cocoons, through the glass sides of 

 the vessels. On one occasion when a number of puparia of Musca 

 occupied by Necrobia were broken open, immediately the adult beetles, 

 with fully developed colouring, ran actively out. Kemner ((13) p. 199) 

 found that the pupal stage of Corynetes coeruleus (in captivdty) lasted 

 about a month. 



Habits of adult beetles. Besides running actively, in the warm 

 breeding-rooms the beetles frequently flew. They did not shun light as 

 completely as do the larvae, for, though frequently found under masses 



' Taschenberj; (I.e.) makes some remarks on tlie composition of tiu' « iiite secretion and 

 cites Oirard (Trnile e'lemenlaire cVKiit. vol i, 1873, p. 541) to the effect that C'lerid larvae 

 pupate in cells which tliey line with a secretion which appears to exude ("suinter") from 

 the body, and that they collect it by scraping the abdomen with tlie mandibles. How far 

 this is correct I cannot say; it does not sound very ])robablc. Cholodkovsky (1,2) describes 

 and figures two large roundish glands, opening one on either side of the anus in the adult 

 jV. rvficolUs : can they be larval secreting glands persisting in the adult ? Perris (( 19) p. 51 ) 

 supposed the secretion to be from the anus. Kemner ((13) p. 197) thinks that in Opilo 

 donip.itirus it comes from the mouth, because he always found tlie head turned towards 

 the lid of the pupal cell, wiiich lid is formed by the larva out of fragments of wood cemented 

 together by the secretion. 



