68 INSECT TRANSFORMATIONS. 



firmly to the abdomen. Having put it into a glass, 

 he remarked a few days afterwards, that the spider 

 had spun the outline of a vertical web, had stretched 

 threads from the top to the bottom, and from one 

 side to the other of the glass, together with the rays 

 of a net, but without the circular threads. The most 

 singular circumstance was, that the parasite grub was 

 suspended in the centre of this web, where it spun its 

 cocoon, while the exhausted spider had fallen dead to 

 the bottom of the glass.* 



These examples will suffice to prove the anxious 

 care of the mother insects in depositing their eggs 

 where their progeny may find abundance of food. 

 The tact with which they discover this is one of those 

 mysteries of nature which are apparently beyond 

 the penetration of man ever to discover; for it is 

 seldom that the mother insect herself feeds upon the 

 same, or similar substances, as her larvse, and yet 

 she is well aware of what is appropriate for them. 

 The ichneumon flies, whose history we have just 

 been sketching, eat little, except, perhaps, a small 

 quantity of honey from the nectary of a flower, 

 and yet they know that their progeny must be 

 fed by living insects; the butterflies and moths, 

 whose scanty repast also consists solely of the honey 

 of flowers, never make a provision of this for their 

 caterpillars, but deposit their eggs on plants and 

 trees where their young may cat abundantly of 

 leaves or other parts ' after their kind.' In making 

 these selections, each species exhibits some pecu- 

 liarity well worthy of observation. Some confine 

 themselves to one particular sort of plant, and never 

 select any other; some make choice indifferently of 

 two or three sorts; while others take a wider range, 

 and fix upon plants of very different qualities. To 

 exemplify this, we might mention some thousands of 



* De Geer, Memoires, vol. ii, p. 863. 



