146 



The Naturalist. 



apparent absurdity in the work of vitality, is nevertheless as impor- 

 tant and useful a requisition as the former. One adds, the other 

 abstracts. We observe this principle involved in every phase of 

 creation : without it, existence would be at cross purposes with itself, 

 and obliteration must inevitably and indisputably ensue. Greater- 

 bodied and consequently less prolific animals are, then, exterminated 

 by the fearful fertility of minor ones. To counteract this obviously 

 depressing and fatal superabundance, enemies are provided which 

 keep a constant checkstring upon over-production, adjusted appa- 

 rently to a nicety. To this class of benefactors (as we may safely 

 call them) the family in question belongs. Par exemple, we are all 

 aware how very common Pieris brassier, the familiar white butterfly, 

 is throughout the summer. We all know that the food upon which 

 the larva regales itself (garden cabbage, &c.,) is exceedingly abun- 

 dant, and we know also how rapaciously the caterpillar eats, how 

 rapidly it grows, how sudden are its metamorphoses, how fertile is the 

 female insect. In short, then, if Brassica were permitted to breed so 

 extensively with impunity, our cabbages would as extensively dis- 

 appear, and we should be burdened with grubs instead of cabbages. 

 What is the remedy ? Some agency must be invoked to arrest the 

 evil. And thus our little microgaster, by name Apauteles glomeratus^ 

 of world-wide renown, comes forward and renders the needful assist- 

 ance. Anyone of an observant disposition . will have noticed, in the 

 summer time, a lot of small silky cocoons of a beautiful yellow hue, 

 clustering about the niches or under the eaves of walls, and in various 

 places, sometimes enclosing in their embrace the dead carcase of 

 larval Brassim They are the progeny of Glomeratus, at once the 

 fiend of common white, and the gardener's friend. To breed and 

 observe these tiny insects through all their stages and movements 

 will repay us tenfold. 



CHAPTER II. LIFE HISTORY. 



" Every mind was made for growth, for knowledge, and its nature is sinned 

 against when it is doomed to ignorance." 



Having granted the utility and actual necessity of these insects, we 

 would wish to see them in the act of warfare. Where can we do so ? 

 Let us take a trip into the woods, and scan the hedgerows as we 

 journey, and, with time and patience, we may be rewarded. I say 

 may, because it is much easier to study the effect than to discover the 

 cause at work. It is possible to watch a caterpillar for a whole 

 afternoon without the least approach of an ichneumon, but defeat 

 must be defeated by re-application, and I do not doubt that ultimately 



