United States or Saint Lucia ? Vote for the TOP Country of the Week !
The precocity of metamorphosis varies from one larva to another; however, a few days' difference of age is enough to explain these inequalities of development. Lastly, there are some, indeed many, which contain a singular egg-shaped shell, divided into segments with projecting breathing-pores.
Just back of the wings is a pair of balancers, short thread-like processes knobbed at the end. These probably represent the second pair of wings with which most insects are provided, and seem to serve as balancers or orienting organs when the insect is flying. On the sides of the thorax are two small slit-like openings, the breathing-pores.
This is the larva of the Sitaris in its new form. With the aid of a lens we can distinguish the fluctuations of the digestive canal, which is gorging itself with honey; and along the circumference of the flat, elliptical back we perceive a double row of breathing-pores which, thanks to their position, cannot be choked by the viscous liquid.
There is one leaf on which there are over one hundred and fifty thousand. They are called stomata, or breathing-pores, and are on both sides of the leaf in most plants, but usually are in far greater abundance on the lower side. The plant draws its food from the air and soil from the latter in liquid form and this substance must be concentrated and assimilated.
But in point of fact, as studies of a later generation were to show, it is the under surface of the leaf that is most abundantly provided with stomata, or "breathing-pores." From the stand-point of this later knowledge, it is of interest to follow our author a little farther, to illustrate yet more fully the possibility of combining correct observations with a faulty inference.
These are the openings into the tracheal or respiratory system. The long cylindrical abdomen is composed of eight segments. These are rather strongly chitinized above and below, but a narrow strip along the side is unchitinized. In this strip are situated the abdominal breathing-pores.
The leaves of land-vegetation have also thousands of little breathing-pores, principally on the under side: the apple-leaf, for instance, has twenty-four thousand to a square inch.
Word Of The Day