236 Variation in the Mealworm, Tenebrio molitor 



When the pupae are examined on the ventral side the last segment 

 shows the aspect in the </ and the % reproduced in Fig. 8. The 

 following differences can be stated. 



Tenebrio molitor 



Fig. 8. 



a. On the last or 13th segment arise the two diverging spines. 

 This segment is deeply cup-shaped, partially surrounded by a semi- 

 annular thickened edge (w) which encloses the segment laterally and 

 distally. The proximal edge of the segment is not visible as it is 

 covered by the distal edge of the last segment but one (12th). In the 

 (/ some four little knobs, like pin's heads, lie against and under this 

 distal edge of the 12th segment in the proximal part of the cup- 

 shaped hollow (or sometimes filling up this hollow for the greater 

 part). The two proximal knobs form one whole, meet each other in a 

 slightly curved line, and cover partly the two distal ones, which are 

 more independent and separated from each other. 



In the female only one pair of knobs is found, fused with each other, 

 and these project farther in the hollow of the segment than the first 

 pair in the male. Moreover these knobs are not round but drawn to a 

 point. 



A further acquaintance with the literature showed that Saling, too, 

 had already observed these sex-differences between the cT and $ pupae, 

 but without figuring them. There are still 3 other differences, which 

 Saling probably did not see, as he does not mention them. They 

 are less conspicuous, but if one knows them, they are distinct enough 

 to be applied as tests in case of doubt. These differences are the 

 following : 



b. The distal edge of the last segment but one has in the $ the 

 form of the vertical section of an U iron, the corners of Avhich are 

 rounded, whereas this form in the cT approaches a semi-circle. 



