422 
J. BRONTE GATENBY. 
preserved in Flemming with reduced acetic acid, and from 
wliicli PL 24, figs. 24 and 27 were drawn, the inner substance 
of the mitochondria appeared to stain a very faint greyish 
tint after prolonged treatment in iron-alum haematoxylin, but 
this is the only case I found in all my material. Judged from 
seven species of Lepidoptera belonging to different families, 
it seems that, generally speaking, the mitochondrial bodies of 
the spermatocyte at the end of the growth stage are of the 
same general shape (spherical to ovoid) throughout, but 
differences exist more particularly not only in the propor- 
tionate size, but also in the number of these cytoplasmic 
structures in the cell. In not every species do the mito- 
chondrial bodies resemble one another either in shape or 
staining affinities. PL 24, fig. 22 depicts the spermatocyte of 
Pieris brassicas. The mitochondria are relatively small 
and spherical, being crowded towards one side of the cell. 
Some of these are seen to be somewhat compressed and 
irregular, and none is found in any. cell process. The darker 
bodies, marked A.B., are the acroblasts, and they are more 
conspicuous than the mitochondria. 
Measurement showed that the size of the mitochondria of 
the several species dealt with was as follows, the average 
being taken in each case, for, as already pointed out, these 
bodies vary in size : 
Orgyia antiqua, diameter of average full-grown mito- 
chondrial body, 2 microns (M eves’ fluid). 
Sme rin thus populi, 1 micron (Champy). 
Pygaera bucephala, 1*5 microns (Champy). 
Pieris brassicae, 1 micron (Flemming without acetic). 
Spilosoma lubricipeda, *5 micron (Flemming with- 
out acetic). 
Vanessa urticge, - 5 micron (Regaud solution). 
The above measurements give the average diameter, but it 
should be remembered that one could easily find a mito- 
chondrial body in Orgyia as small as the average of Spilo- 
soma. Some forms show a great tendency to variation in- 
size (Orgyia), whilst others are more uniform (Smerinthus), 
