LONDON INSECTS 91 



almost every kind, one would have supposed it impos- 

 sible that an animal should live for many days with 

 another creature of comparatively large size living and 

 eating in its tissues, without dying of blood-poisoning, 

 or whatever else may be its equivalent in an insect. 



But this danger is avoided by a most strange 

 peculiarity of construction which is found in the larvse 

 of such parasitical Flies and of Bees. If any one wishes 

 to know how it is that a beehive is sweet, in spite of 

 the crowds of hungry Grubs .crammed into it, or why 

 the juices of a Caterpillar attacked by an Ichneumon 

 are not fatally tainted, he may read a reason in No. 

 XVIII. 1 of Professor Owen's Lectures on Invertebrate 

 Anatomy. 



In England, if a Caterpillar or Grub escapes the 

 ordinary diseases to which insects, like all of us, are 

 liable, and is lucky enough to be overlooked by birds, 

 beasts, and other insects, it may, so far as we know, 

 be pretty sure in good time of beginning life again as 

 a Butterfly, or whatever else it may be intended to 

 become. 



But in other countries there is another danger to be 

 met. In the Insect-house in the Zoological Gardens 

 is a case containing what looks like stalks of coarse, 

 irregularly-grown grass, with heavy clumped roots. 

 They are specimens of the larvre of the New Zealand 

 Swift Moth the so-called 'vegetating Caterpillar,' 

 which, as the note in the case explains, is liable to the 

 attacks of a fungus (Sphceria Eobertii) which attaches 



1 See Appendix C. 



