Packard.] 
INSECTS OF THE GARDEN. 
9 
both sexes, while the autumnal brood is composed exclu¬ 
sively of females. Again in some species of moths where the 
two sexes are of equal abundance Von Siebold found that it 
was no unusual thing for individuals to be hatched from eggs 
known to be laid by a previous virgin generation. 
Fairly entered upon the duties of active life the young 
larva is capable of doing wonders in gastro-dynamics. It 
would seem with most insects as if all the eating for their 
lives were concentrated into this stage of their existence. 
For there is a period coming of long cessation from activity, 
when, in external immobility and seeming lethargy, wonder¬ 
ful transformations pervade nerve and muscular tissues; a 
new body, wonderfully differentiated for a new existence in 
a far more extended sphere than formerly, is taking on its 
form beneath the rough and often unsightly pupa. 
After the last moulting the power and desire, of eating are 
lost, increased stores of fat are laid up for the sustenance of 
the pupa, and the wings and legs of the future fly are forming. 
The worm seeks a shelter and often spins a cocoon of silk, 
and there, in quiet and away from the light, its functions of 
animal life suspended and a very slow vegetative existence 
barely sustained, as a chrysalis the insect spends a portion 
of its life. 
The knowledge of the fact that all animals pass through 
some sort of a metamorphosis is very recent in physiology; 
moreover the fact that these morphological eras in the life of 
an individual animal accord most unerringly with the grada¬ 
tion of form in the type of which it is a member, was the 
discovery of the eminent physiologist' Von Baer. Up to 
this time the true significance of the luxuriance and diver¬ 
sity of larval forms had never seriously engaged the atten¬ 
tion of systematists in entomology. 
What can possibly be the meaning of all this putting on 
and taking off of caterpillar habiliments, or in other words 
the process of moulting, with the frequent changes in orna- 
9 
