54 THE DURATION OF LIFE. [I. 



stings of the workers, but by these latter driving away the 

 useless drones from the food so that they perish of starvation. 



Wasps. It is interesting that among these near relations of 

 the bees, the life of the female should be much shorter, corre- 

 sponding to the much lower degree of specialization found in the 

 colonies. The females oiPolistes gallica and of Vespa not only laj'- 

 eggs but take part in building the cells and in collecting food ; 

 they are therefore obhged to use all parts of the body more 

 actively and especially the wings, and are exposed to greater 

 danger from enemies. 



It is well known from Leuckart's observations, that the so- 

 called 'workers ' of Poh'sfes gallica and Bombus are not arrested 

 females like the workers of a bee-hive, but are females which 

 although certainly smaller, are in every way capable of being 

 fertilized and of reproduction. Von Siebold has nevertheless 

 proved that they are not fertilized, but reproduce partheno- 

 genetically. 



The fertilized female which survives the winter, commences 

 to found a colony at the beginning of May : the larvae, which 

 hatch from the first eggs, which are about fifteen in number, 

 become pupae at the beginning of June, and the imagos appear 

 towards the end of the same month. These are all small 

 ' workers,' and they perform such good service in tending the 

 second brood, that the latter attain the size of the female which 

 founded the colony ; only differing from her in the perfect 

 condition of their wings, for by this time her wings are greatly 

 worn away. 



The males appear at the beginning of July ; their sperma- 

 tozoa are mature in August, and pairing then takes place with 

 certain ' special females which require fertilization ' which have 

 in the meantime emerged from their cocoons. These are the 

 females which live through the winter and found new colonies 

 in the following spring. The old females of the previous winter 

 die, and do not live beyond the summer at the beginning of 

 which they founded colonies. At the first appearance of frost, 

 the young fertilized females seek out winter quarters ; the 

 males which never survive the winter, do not take this course, 

 but perish in October. The parthenogenetic females, which 

 remain in the nest during the nuptial flight, also perish. 



The males of Polistes gallica do not live longer than three 



