OBSERVATIONS ON INSECT LIEE 181 



contained larva, it would stand over the spot, violently 

 vibrate its wings for a minute or two, and continue 

 to repeat this remarkable process until the draught 

 of air, thus produced, had sufficiently cooled the 

 cell. I never saw workers cooling any part of the 

 comb except that warmed by the early morning sun, 

 nor did they ever fmd any necessity to do so once 

 the sun had so risen in the heavens as to be no 

 longer able to peep beneath the overhanging verdure. 

 It was by means of the antennae that the wasp ap- 

 peared to judge if the cell required cooling, so that 

 I suspect that the antennae, in addition to other 

 functions, also possess the sense of judging changes 

 in temperature. 



This cooling of the cells by fanning is probably a 

 satisfactory process. It is not a customary habit of 

 Polistes, as the species seldom hangs its nest in a 

 sunny place. We may perhaps regard it as an early 

 stage in the evolution of that far more complex system 

 by which relays of workers, all fanning in regular 

 order, can ventilate with a fresh current of air the 

 dark hive of the honey-bee. 



There is another slight resemblance between the 

 Polistes and the honey-bee. Polistes loves to suspend 

 its nest from the roofs of dark verandahs or the ceilings 

 of disused rooms, yet it sometimes chooses to build in 

 the shelter of a thick bush, or even on the branch of 

 an exposed tree. The hive-bee also, especially the 

 form known as Apis dorsata, has been known to build 

 in the open when no hollow tree is to be found. It 

 probably once possessed the habits of Polistes, some- 

 times building on an exposed branch, but usually 

 seeking a shady place ; and when now a European 



