3 6 
Development and Metamorphosis 
born alive, after having passed a considerable time growing and developing 
in the body of the mother. And this difference in degree of development at 
birth is largely due simply to the difference in amount of nourishment 
which can be afforded the young. The embryo in the egg uses up its food 
early in its developmental career and before it has reached the stage of 
likeness to its parents. It issues in a condition picturing some far-distant 
ancestor of its species, or more frequently, perhaps, in a modified, adapted 
condition, fit to make of this tender unready creature thus thrust before 
its time into the struggle for living an organism capable of caring for itself, 
although not yet endowed with capacities as effective as, or even similar to, 
those of the parent. 
It is familiar to us, then, that development is not wholly postnatal or 
postembryonic; that before birth or hatching a greater or less amount of 
development, requiring a longer or shorter 
period of time, has already been undergone. 
Every animal begins life as a simple cell; all 
animals except the Protozoa (the simplest ani¬ 
mals, those whose whole body for its whole 
life is but a single cell) finish life, if red 
Nature permits them to come through myriad 
dangers safely to maturity, as a complex of 
thousands or millions of cells united into 
great variety of tissues and organs. This 
great change from most simple to most complex 
condition constitutes development: the actual 
increase of body-matter and extension of 
dimensions is growth. 
Most insects hatch from eggs; being bom 
alive is the exceptional experience of the young 
of but few kinds, and even this is a sort of 
pseudo-birth. Such hatch alive, one may better 
say, for they begin life in eggs, not laid out¬ 
side the mother body to be sure, but held in 
the egg-duct until hatching-time. With very few exceptions, young insects 
are not nourished by the mother except in so far as she stores a supply of 
yolk around or by the side of each embryo inside the egg-shell. The form¬ 
ing of the egg is a matter which does not lend itself readily to the observa¬ 
tion and study of amateurs, but is a phenomenon of unusual interest to 
whomever is privileged to discover it. The insect ovaries consist of a pair 
of little compact groups of short tapering tubes (Fig, 66). In the anterior or 
beginning end of each tube is a microscopic space or chamber from whose 
walls cells loosen themselves and escape into the cavity. These cells become 
Fig. 66 .—Ovaries and oviducts 
of a thrips. o.t., ovarial tubes; 
o.d., oviduct; r.s., seminal 
receptacle, or spermatheca; 
d.r.s., duct of the seminal re¬ 
ceptacle. (After Uzel; much 
enlarged.) 
