GLANDS OF ELYTRA. 



91 



Table 32. Variation in per cent of frequency in the glands of the elytra in L. undecim- 

 lineata, L. signaticollis, L. multitaniata, L. oblongata, L. decemlineata, L. juncta, L. 

 rubicunda, L. lineolata, L. dilecta, L. calceata, L. haldemani, L. violescens, L. libatrix, 

 and L. rubiginosa. 



L. undecimlineata : N. = 1,000 individuals. 



L signaticollis : N. = 1,000 individuals. 



L. multitceniata : N. = 2,200 individuals. 



L. oblongata : N. =600 individuals. 



L. decemlineata : N. = 5,200 individuals. 



L. juncta ; N. =200 individuals. 



L. rubicunda : N. = 100 individuals. 



L. lineolata : N. = 300 individuals. 



L. dilecta : N. = 100 individuals. 



L. calceata : N. = 100 individuals. 



/.. haldemani : N. = 200 individuals. 



L. violescens : N. = 100 individuals. 



L. libatrix : N. = 100 individuals. 



L. rubiginosa : N. =100 individuals. 



OBSERVATIONS AND DATA CONCERNING EXTREME VARIATIONS. 1 



Observations upon variations of this class must of necessity be scanty, 

 excepting in experiment, and even there they are not abundant. In nature 

 several extreme variations have been found. The best and longest known 

 of these is the species L. melanothorax , which occurs as a variation of 

 L. multitaniata, but does not become a permanent species. It differs from the 

 parent in general appearance, shape, and color, in the black pronotum and 

 ventral surface, and in the fusions of the two subcostal stripes on the elytra. 

 On plate 16 is represented in fig. 4 the parent species, multitaniata, in life, 

 and in fig. 5 melanothorax. A second extreme variation from multitaniata 



1 1 have used " extreme variation " or " extreme variate " in place of " discontinuous 

 variation " and " mutant " because there is no real discontinuity in these variations, but 

 a rapidly developed extreme deviation from the parental state. 



