ix] ACULEATE HYMENOPTERA 127 



or of rotten wood containing known larvae or pupae 

 in a small piece of gauze or tiffany. Such precautions 

 have the further advantage of making quite sure of 

 nesting sites of species whose larvae have perhaps 

 not been identified at the time of capture ; and such 

 are certain to be numerous. 



It perhaps "goes without saying" that some degree 

 of patience and of perseverance in the face of disap- 

 pointments is necessary in these rearing operations ; 

 but they are worth the trouble. 



Several more or less successful attempts have been 

 made to keep social species under artificial conditions 

 as similar as possible to those that would be found in 

 the open. Wasps have been induced to build their 

 nests in glass-sided cages in principle not unlike the 

 familiar "observatory hives" used by demonstrators 

 in apiculture. The most convenient species for this 

 purpose are those social -wasps which attach their 

 nests to the branches of shrubs or trees. Such nests 

 can be removed whole and without any disturbance 

 of their occupants by carefully cutting through the 

 branch, with as little vibration as possible, in the 

 late evening when all the wasps are at home. A 

 prudent precaution is first to surround the entire 

 nest with the bag of a butterfly net, or some similar 

 material. I have tried repeatedly to get queen wasps 

 to continue their operations in captivity by taking 

 their little nests while the queen was within, and 



