272 



GENERAL BIOLOGY 



The Care of the Young. Another type of adapta- 

 tion of very great value to the species in which it is 

 developed is that involved in parental solicitude and 

 care for progeny. Among the lower forms, par- 

 ticularly the invertebrates, the rule is for the mother 

 animal to lay an enormous number of eggs and 

 trust to luck, so to speak, that 

 enough survive to maintain the 

 position of the species. In many 

 of the insects, however, this is 

 not at all the case. The workers 

 in a beehive or an ant hill attend 

 and feed the helpless grubs until 

 they are ready to shift for them- 

 selves. Among certain of the 

 wasps, the mother, although de- 

 FIG 96. Water Bug pending for her own food upon 



(Zaitha). Male earrying l . 



eggs on its hack. (From nectar sipped from flowers, yet 

 catches flies for her carnivorous 

 young. Finally we have a situation such as is to be 

 observed in Zaitha^ one of the water bugs, in which 

 the female seizes the weaker male, and in spite of 

 his struggles, glues her eggs all over his back, trans- 

 forming him, for the time being, into a nurse. 



A somewhat similar example is to be found in the 

 Surinam toad, Pipa. In this species, the female 

 places the eggs on her own back, where they sink in, 

 forming little pits that close over. When ready to 

 hatch, the covers break off and the baby toads 

 wriggle down to water to complete their metamor- 

 phosis. In another kind of toad, Alytes, the male 



