S. A. Arendsbn Hein 231 



Entirely or partially fused may be 



the 2nd + 3rd segments. Fig. 2, Nos. 1, 2 



„ 3rd+ 4th „ „ 2,3,4,5,6,7 



„ 4th + oth „ „ 6,8,9,10,11 



„ 5th + 6th „ „ 6, 12, 13, 14 



„ 6th + 7th „ „ 6, 12, 14, 15, 16, 17 



„ 7th + 8th „ „ 17, 18, 19 



„ 8th + 9th „ „ 9, 20, 21 



„ 9th + 10th „ „ 9, 13, 22 



„ 10th + 11th „ „ 24, 25. 



From the 2nd, 3rd and 4th segments spring the larval legs. When 

 these segments are partially fused it may occur that the two fused 

 halves carry only one leg, as is the case in No. 3 and No. 7, 



In No. 3 the right hand half of the 3rd segment was fused with the 

 corresponding half of the 4th segment ; the right leg of the 3rd segment 

 had not been developed. The same phenomenon presents itself in 

 No. 7, where the right leg of the 3rd segment was wanting. 



Remarkable is also the instance given in No. 6. Here several 

 segments are partially fused in such a manner that the connecting 

 ligament between the segments form a spiral line. 



When examining a population of larvae, supplied by the trade, I 

 found, in any 300 or 400 larvae, one with an abnormal segment. The 

 10,000 individuals examined yielded 35 larvae with abnormal segments. 

 Of these 18 beetles could be bred, which were paired. 



Successively three generations were bred from them. The ^i gene- 

 ration produced only one abnormal larva. In the F2 generation among 

 the 884 larvae there were seven with abnormal segments. The F^ gene- 

 ration of these seven larvae was, however, normal again. Afterwards 

 the experiment was repeated once more on a larger scale with larvae 

 from my own cultures. Among 38,800 investigated larvae there were 

 62 with abnormal segments. 



A segmental anomaly maintains itself in the pupa, of which some 

 instances are figured in Fig. 3, 1 — 4, and once more in the beetle, where 

 it causes strange deformities. One of these monstrosities is shown 

 in Fig. 4. The prothorax consists here of two halves lying symmetri- 

 cally to the median line and forming two equilateral triangles, whose 

 tops point to each other. Not always are these halves so equal and 

 similar as is shown in the figure. Sometimes one of the halves is more 

 strongly developed than the other, or is deformed by dints and deep 



