NEW YORK STATE MUSEUM 



59 



metal top being finely perforated to admit air. The following 

 tabulation summarizes the data. 



Tribolium confusum, biological data 



Jar 



A 



B 





C 



D 





E 





F 



G 



1918 



A' 



G = 



A 



G 



A 



G 



A 



G 



A 



G 



A 



G 



A 



G 



May 27 



2 





4 





4 





2 

















June 18 



2 



2 



4 





4 



2 



2 

















July 6 



2 



20-30 



4 





4 



12 



2 



9 















16 



2 



40 



4 





4 



25 



2 



10 



2 





4 





2 





23 





40 



4 







24 





7 



2 





4 





2 





Aug. 8 











1 



r2 4 



5 



?I0 



2 



?S 



4 



?5 



2 



rs 



17 



6 



?20 



4. 





1 



:>2 4 



15-20 





2 



?5 



4 



?S 



2 



'5 



29 



18 





4 





19 



? 



18 





2 



?7 



4 



?5 



2 



'7 



Sept. s 



ai8 





4 





18 



1 



17 





2 



?7 



9 



?7 



S 



r7 



H 



20 





4 





18 



?3 



17 





3 



?6 



9 



?7 



6 



r6 



21 



bl9 





4 





22 



1 



18 





3 



?6 



8 



?7 



7 



'5 



28 



21 





4 





20 





18 





3 



?6 



8 



?7 



7 



.'5 



Oct. 7 



C17 





4 





16 





16 





9 



2 



9 



?S 



7 



?3 



23 



16 



?5 



3 





16 



1 



16 





12 



3 



9 



2 



8 



<3 



Nov. 19 



17 





3 





15 





16 





II 



2 



9 



?7 



9 



(1 



Dec. 10 



IS 





3 





15 





16 





10 



5 



7 



10-12 



9 



3 



3i 



13 



2 



3 





13 





IS 





II 



S 



7 



10-12 



8 



1-3 



' Adult. 



* Grub. 



a Also two dead. 



b Also two dead. 



c Also one dead. 



Jars A, B, C and D were started May 27th, with 2, 4, 4 and 2 

 adults respectively, and prior to the appearance of another gen- 

 eration of adults, namely, July 16th, the living beetles were trans- 

 ferred from A to jar E, from C to jar F and from D to jar G, 

 and the records under these last three headings really belong with 

 those for A, C and D respectively. It will be noted that a period 

 of 81 days elapsed between the establishment of jar A and the 

 appearance of a second generation of beetles, and in the case of 

 jar C, this was extended to 93 days, while for jar D, the time was 

 reduced to 72 days. , These figures should be checked by those 

 obtaining in jars E, F and G, probably more nearly normal, where 

 the periods were respectively 59, 50 and 50 days. 



The earlier statements credit this insect with being able to com- 

 plete its life cycle under favorable conditions in 36 days. The 

 investigations of Professor Dean in Kansas led him to state that 

 the life cycle in summer may be completed in only 35 days while 

 with a temperature of 70 degrees from 98 to 105 days are neces- 

 sary. Our data were obtained in a large room in a cool stone 

 building, the summer temperatures being by no means excessive, 

 while those in the cooler months rarely varied much from 70 



