Tenebrionidae 



465 



later) after about 20 days. Pupae, if present, should be isolated by sexes 

 into new and separate containers. This should be kept up until the desired 

 number of pupae have been obtained from each bottle. 



5. It is preferable at this point to select some of these isolated pupae and 

 put them back into new stock bottles with fresh flour, thus completely 

 renewing the stocks. It is important that the flour be changed, as Park 

 (1934a, 1935) has shown that old or "conditioned" flour reduces the 

 fecundity and adversely affects the metamorphosis of the beetles. 



Flour infested with Tribolium may be sifted in such a way as to 

 separate the beetles in all instars from it provided finely ground flour 

 has been used. Chapman (1918, 1928) used standard meshes of silk 

 bolting cloth and found that mesh number 9 would not pass any of the 

 stages but would pass finely milled flour; number 3 segregated eggs and 

 larger larval instars from the flour, and number 000 passed all eggs and 



Fig. 81. — -Diagram of the automatic flour sifter. 1, belt wheel; 2, driving wheel; 3, 

 driving rod; 4, flour sieve; 5, flour sieve holder; 6, removable collecting tray. (From 

 Quart. Rev. Biol., with permission.) 



larvae except the largest instar. Thus, by using appropriate meshed 

 sieves, all stages may be obtained as desired. To aid in this somewhat 

 laborious sieving the author uses a mechanical device (Fig. 81) which 

 automatically shakes the flour through the cloth and collects it in a re- 

 movable tray below. The beetles are retained in the sieve. 



In handling the beetles it is well to be as gentle as possible; the author 

 has found that both brush and small spatula are useful in this regard. 

 In experimental work the adults should be removed from infected flour 

 where possible before sifting since there is some evidence to the effect 

 that too rough handling diminishes the fecundity of the females. 

 (Stanley, 1932). 



In the accompanying bibliography the references have been chosen 

 with the culturist in mind. Most of the material on the biology of 

 Tribolium has been reviewed recently by Park (1934). 



Bibliography 

 Brindley, T. A. 1930. The growth and development of Ephestia kuehniella 

 Zeller and Tribolium conjusum Duval under controlled conditions of temperature 

 and relative humidity. Ann. Ent. Soc. Amer. 23:741. 



