SHORTER ARTICLES AND DISCUSSION 



NOTES ON A DIFFERENTIAL MORTALITY OBSERVED 

 BETWEEN TENEBRIO OBSCURIS AND T. MOLITOR 



I recently had occasion to subject some meal worms for short 

 periods of time to a temperature considerably higher than that of 

 the laboratory. Although the experiment was begun with a dif- 

 ferent purpose in view, there has been one feature noted which 

 seems worth recording at this time. 



The meal worms used consisted of the larva of Tenebrio molitor 

 Linn, and T. obscuris Fabr. These larvse are very readily dis- 

 tinguished from each other by the fact that the pigment in the 

 integuments of T. molitor is yellow to orange-brown, while that of 

 T. obscuris is almost black. In other features the larvae resemble 

 each other to a remarkable extent. 



Experiments with Ki.kvated Temperature 

 The worms were placed in large Stender dishes containing a 

 little meal and the dishes were then placed in a large, constant 

 temperature incubator, being insulated from the bottom of the 

 incubator by a cork ring and care being taken that the glass sides 

 of the dishes did not come in contact with the copper sides of the 

 incubator. The temperature was frequently noted through the 

 glass door of the incubator and was also recorded on a maximum 

 and minimum thermometer placed inside of the incubator and 

 likewise insulated from contact with the copper sides or floor. 1 

 Three major experiments were made after a probable differen- 

 tial mortality had been observed. These experiments are sum- 

 marized below. 



! in an insulated dish 



