1878. ] Physiography. 665 
In Lampyris the almost perpetual play of light, generated and 
partly confined within the posterior segments, has probably con- 
duced to their final change of color. Ozone, of whose presence 
there is a suspicion, possibly exercises its bleaching power here 
as in vegetable tissues. 
Assuming that the phosphorescent material is accumulated in 
the larval and preserved in the pupal stage for the final form, 
there are certain ways in which it might be useful at this latter 
period. The apterous female, being without food, must generate 
sufficient heat, from internal resources, to sustain life through 
oviposition. 
The winged species may also utilize this power to decoy vic- 
tims, and also to betray their presence to the carnivorous species, 
while others may kindle the torch of Hymen by this veritable 
flame. That both sexes possess phosphorescent properties is 
not surprising, since both are the product of a luminous stock, 
but we.may expect a greater degree of phosphorescence from the 
female, and facts sustain this expectation. 
Thus our insect seems eminently conservative in its powers, 
while combining the useful and the beautiful in its physical gifts. 
z0? 
PHYSIOGRAPHY. 
BY C. LLOYD MORGAN, F.G.S., A.R.S.M. 
HE artist who is illustrating a great theme upon a large spread 
of canvas finds it necessary from time to time to lay down the 
brush, with which he is accurately filling in the more delicate 
minutiz, that he may retreat to a distance and view his picture as 
a whole. It is essential to the higher development of his art that 
he should not omit this comprehensive survey. The same thing ` 
holds good in literature and science, as well as in art. The. 
historian must, from time to time, take a fresh survey of history 
as a whole. If he neglect to do so, the group of figures to which 
he devotes his special attention will certainly not take up its true 
position among the other groups that appear on the canvas of 
history. The man of science, also, should not forget that he is, 
according to his individual bent or capacity, aiding in the con- 
struction of a great philosophy ; and he should now and again 
turn aside from the microscope, or lay down the hammer, to take a 
