vi THE DOMESTIC LIFE OF ANIMALS 115 



which is never experienced, it seems probable that there 

 were ancestral forms, living in different climatic condi- 

 tions, which did survive to see their offspring. A not 

 uncommon kind of variation among animals is an altera- 

 tion in the punctuation of the life-cycle a lengthening- 

 out of one chapter and a shortening of another. This 

 may occur in adaptive relation to changed circumstances. 

 It is also plain that types of mother-insect that made 

 bad mistakes in regard to their offspring would be auto- 

 matically eliminated, leaving the race more select. But 

 after thinking out these explanations, the facts remain 

 marvellous. Thus W. Marshall saw an ichneumon fly 

 (Polynema natans) remain twelve hours under water, 

 without special adaptations for such a life, swimming 

 about with her wings, and depositing her eggs within the 

 larvae of dragon-flies ! 



We are accustomed, the same naturalist says, to look 

 upon a hen which gathers her brood under her wings as 

 a picture of loving care, but we must recognise that the 

 same is true of earwigs, spiders, and scorpions. Some 

 naturalists have described the pale-yellowish young 

 earwigs crowding under the shelter of their mothers, w r ho 

 stand guard with open pincers, but there seems to be 

 some doubt as to the accuracy of the observation. 

 Female spiders, too, so fierce and impatient as mates, 

 are most ' respectable mothers." Some make nests, 

 guard, feed, and even fight for the young ; others carry 

 the eggs about with them. " I have often," Marshall 

 says, ' ' made fun of the little creatures, taking aw r ay their 

 precious egg-sac and removing it to a slight distance. 

 It was interesting to see how eagerly they sought, and 

 how joyously, one may even say, they sprang upon their 

 ' one and all ' when they found it again. Sometimes I 

 cheated them with a little ball of wool of the size, form, 

 and colour of the egg-sac, which they quickly seized, and 

 as rapidly rejected." 



Many fishes lay their eggs by hundreds in the water, 

 and thenceforth have nothing more to do with them, but 

 even among these cold-blooded animals there are illus- 

 trations of parental care. From a bridge over the river 



