1887.] NATURAL SCIENCES OF PHILADELPHIA. 369 



PROLONGED LIFE OF INVERTEBRATES : NOTES ON THE AGE AND 

 HABITS OF THE AMERICAN TARANTULA. 



BY HENRY C. MCCOOK, D. D. 



Until very lately little has been known concerning the possibilities 

 of prolonged life among the lower orders of animals. It is well 

 known that the waste of life is very great in the natural conditions 

 surrounding most inferior creatures, so that the immense fecundity 

 of insects and araneads, for example, is abundantly checked. I have 

 counted over eleven hundred eggs and young spiders in the single 

 egg-cocoon of the Bank Argiope, Argiope riparia, yet one of the 

 rarest finds for an observer is a very young individual of this common 

 species. In efforts to breed spiders from the cocoon, I have at various 

 times seen colonies numbering one hundred or more dispersed from 

 the maternal egg nest to the surrounding foliage, of which during 

 the year not a single survivor could be traced. 



Bee keepers are well aware of the great mortality among working 

 bees, caused not only by disease and accidents, but especially by 

 those enemies which prey upon them. Ants are quite as much, per- 

 haps even more exposed to loss from accidents, the exigencies of 

 weather and the appetites of various insectivorous animals. There 

 is, therefore, abundant occasion for the seemingly exhaustless fertil- 

 ity of the queen mothers of formicaries. These queens probably 

 have a longer life than the workers. They are larger in size and 

 apparently organized for more vigorous resistance of the influences 

 which work for their destruction. Moreover, the instinct of the 

 workers has provided a system of preservation by surrounding the 

 queen with a guard of attendants which never leave her unprotected, 

 which care for all her wants, and vigilantly separate her by a reg- 

 ular system of seclusion within the portals of the formicary, from 

 many influences which would prove hostile to health and fatal to 

 life. 



I. Sir John Lubbock's Aged Ant Queen. 



How long an ant queen may live in entirely natural habitat is 

 unknown, and perhaps cannot be determined. But recently through 

 the patience and ingenuity of Sir John Lubbock, Ave have learned 

 that under artificial protection both workers and queens of certain 

 species may attain a great age. Nearly six years ago I had the 

 privilege of visiting this distinguished naturalist at his country seat, 

 High Elms, Kent, and examining, under his personal direction, his 



