240 Variation in the Mealworm, Tenebrio molitor 



It is not the design of this paper to enter into particulars about 

 this problem, the less so, because later on I shall refer to it again with 

 more complete documentary data. Here I only draw attention to 

 the fact that, independent of the season, the smallest individuals of a 

 certain culture appear in a decided preponderance in the beginning, 

 the larger beetles in a later period of that same culture. 



The following table and curves (in which also the values characteristic 

 of the three variation-series are stated) give a graphic illustration of the 

 fact mentioned. 



1st thousand 



2nd 



3rd 



Number 



of 



individuals 



measured 



n 



1000 

 1000 

 1000 



Average length 



Af±7ft 



Mean ± 

 probable error 



12 -98 ±0-033 

 13 -88 ±0-056 

 15 -49 ±0-041 



Standard 

 deviation 



SpD" 



/ 

 T=r\l- 



1-0553 

 1-6031 

 1-3141 



Coefficient 



of 

 variability 



100<r 



8-13 

 11-55 



8-48 



Skewness 



S 



Excess 

 E 



,.i^.,^ --(??-'-)-' 



- 0-064 

 + 0-120 

 -0-06 



+ 0-237 

 -0-263 

 + 0-100 



When determining the coefficient of variability for the males and 

 females separately, I found it for the males to be higher than for the 

 females, and this was so in each of the 3 series of 1000 pupae. The 

 exact figures are : 



let thousand 

 2nd „ 

 3rd 



Males 



8-57 



1207 



8-95 



Females 



7-52 



10-86 



7-92 



Average v = 12-52 



11-50 



