io6 The Study of Animal Life parti 



In many of the lower animals the units which begin 

 new lives are readily separated from the parent ; but in 

 others, e.g. some of the simplest, or some by no means 

 simple "worms," and even some insects, the parent life 

 disappears in giving birth to the young. Reproduction or 

 the continuance of the species often involves a sacrifice of 

 the individual life. 



It is strangely true, even in the highest forms, that 

 reproduction, though a blossoming of the whole life, is also 

 the beginning of death. It is costly, and brings death as 

 well as life in its train. This is tragically illustrated by 

 many insects, such as butterflies, who die soon after repro- 

 ducing, though often not before they have, in obedience to 

 instinctive impulse, cared most effectively for their eggs — 

 the results of which they do not live to see. Think also of 

 the mayflies, or Ephemeridae, who, after a prolonged aquatic 

 life as larvffi, become winged, dance in the sunlight for an 

 hour, mate and reproduce, and die. 



Picture the long larval life in the water, and the short 

 aerial happiness lasting for an evening or two. Long life, 

 compared with the span of many other insects, but short 

 love ; there may be years of patience, and but a day 

 of pleasure ; great preparations, and the anti-cHmax 

 of death. The eggs lie half conscious in the water, 

 faintly stirred by the growing life within, lapped round 

 about by peace, — though the trout thin them sorely. 

 In the survivors the embryos become conscious, awaken 

 from their rocking, and turn themselves in their cradles. 

 See the larva creep forth, wash themselves gaily in 

 the water, and hungrily fall upon their prey, some 

 smaller insects. The little " water-wings " grow, and 

 the air soaks into the blood ; the larvae cast their skins 

 many times, and hide from the fishes. At length comes 

 the final moult, and the making ot the. air-wings, of which 

 in the summer evening you may see the first short flight as 

 the insects rise like a living mist from the pool. But even 

 yet a thin veil, too truly suggestive of a shroud, encumbers 

 them ; and they rest wearily on the grass or on the 

 branches of the willow. Watch them writhe and jerk, as if 



