[Illustration: _Pupa of the Ephemera, showing its gill-like Organs._]
All pupæ of aquatic habits do not, however, possess this remarkable faculty of surrounding themselves with air even in the midst of the water; and these would certainly perish unless means existed for them also to inhale the vital air. These means are found in the endowment of them with the power of swimming. Surely our readers must often have seen the wriggling movements of certain little blackish objects, which are to be found in every stagnant puddle in the summer. Many of these are the pupæ of various species of gnats; and when we watch them come darting upwards by a succession of flaps with their tail, until they reach the surface, where they remain for a short time, we see the means by which, although they live immersed in water, they are enabled to breathe the air. For if we scrutinized them a little narrowly, we might detect on each side of their largest extremity or head, a pair of minute tubes which open into the air at the surface of the water. It may sink beneath the water for a time without inconvenience, and it is soon found plunging upwards, anxiously seeking to thrust its tubes into the air. In the _larva_ state the gnat breathes by its tail, in the pupa state by its _head_! The pupæ of some aquatic insects breathe like the larvæ of the same insects by organs like gills. That of the ephemera shown on the last page is an instance.
The curious apparatus of a telescope-like air-tube of the rat-tailed insects, described in a former page, will not be forgotten by the reader. It may interest him to learn that there is another little creature which, in the pupa state, is furnished with a somewhat similar apparatus. These pupæ have not the same power of swimming with the last, and therefore require a special provision to meet the necessities of their case. They are plunged some way down in the water, and air is conveyed to them by a hollow tail-like tube, which is always found to open on the surface of the water. It is a curious thing to contemplate these little creatures, so beautifully provided for in this manner. Secure of all they need in the supplies of air furnished to them by their tube, they rest peacefully in the waters, unmoved by any of the accidents which occur to surrounding creatures, and patiently awaiting the hour which is to behold them rise from their watery bier, never more to return. Let us so likewise rest in assurance of our Heavenly Father's love and care for us, knowing that every want will be supplied to his children by Him, who has said, "I will never leave thee nor forsake thee."