IV] DIPLOPTERA 53 



supplies plentiful that worker larvae in consequence 

 of their generous diet become fertile (parthenogene- 

 tically); their eggs however produce only drones. 

 Hence the drones of any given community may be 

 either sons or grandsons of the foundress "queen"; 

 but in all cases they arise from unfertilised eggs: 

 they are usually reared in ordinary, but sometimes 

 also in "royal" cells. 



If a comb from the centre of a nest in full activity 

 be examined, it will be seen how that the "queen" in 

 her egg-laying journeys travels round and round the 

 comb in fairly regular circles. The marginal cells of 

 such a comb will perhaps contain eggs but lately laid ; 

 the next band will contain young larvae, the next 

 rather older, and the next full-grown larvae ; then 

 follow circles of "capped" cells (i.e. with the dome- 

 shaped cocoon projecting) containing pupae or perhaps 

 young wasps just ready to emerge : still nearer to the 

 centre occurs a circular belt of cells just vacated; 

 these are followed by cells that have been tidied by 

 the workers and have lately received from the queen 

 an egg for the second time ; and then the whole series 

 of stages is repeated again, circle after circle, as we 

 pass towards the centre which is the oldest part of 

 the cornb. 



In the course of a good season the population 

 reared in a fair sized wasp's nest is very numerous. 

 Janet counted 11,500 cells in a nest containing but 



