221 THE BUTTERFLY VIVARIUM. 



Vivarium. There are several very distinct kinds, 

 but I have not space to enumerate them here. 



I must, indeed, only refer to one more family of 

 Insects in the order Neuroptera — that of the pretty 

 green insects with transparent wings seen fluttering 

 about the shady parts of our gardens in the warm 

 summer twilight. The most common species is 

 Chrysopa Perla, both the generic and specific names 

 of which convey the idea of its transparent wings 

 with their opalline tinges of milky softness, flushed 

 in different lights^with prismatic hues, which have 

 sometimes the effect of the nacreous colours of some 

 of the most beautiful of the pearl-lined sea shells. 

 The female Chrysopa should be placed in the Insect 

 Vivarium, in order to secure an opportunity of see- 

 ing the curious disposition of the eggs at the top of 

 slender filaments, as described in Chapter IV. The 

 larvae of this insect, when hatched, creep down the 

 hair-like stilts upon the eggs, which have been 

 placed as a security against predatory enemies, and 

 immediately commence their own depredations among 

 the Aphides, which are their natural prey. The larvae 

 of the genus Chrysopa resemble in general form, and 

 in the nature of their food, those of the Lady -bird, to 

 be described in another place, though the perfect insect 

 belongs to such an entirely different class of insects. 



