XXV INSECTA . HYMENOPTERA 399 



Division 2. Diplotera. Wasps having the front wings folded 

 once longitudinally when at rest ; eyes kidney- 

 shaped. 

 Family 2. Vespidae. Social wasps with three castes of 

 individual. 



Genus. Vespa. 

 Family 3. Eumenidae. Solitary true wasps, no " worker " 

 caste developed. 



Genera. Eumenes. Odynerus. 

 Division 3. Fossores. The Digging Wasps. Solitary carnivor- 

 ous forms, front wings not folded when at rest, 

 eyes not kidney -shaped, no " worker " cast«. 

 Family 4, Pompilidae. " The Running Wasps." 



Genus. Pompilus. 

 Family 5. Sphegidae. " The Sand Wasps." (A large collec- 

 tion of forms, alike in the nature of the thorax ; 

 the family should perhaps be broken up.^) 

 Genera. Sphex. Ammophila. Mellinus. 

 Grabro. Gerceris. 



Practical Work on Wasps 



1. Hunt for a wasps' nest on a sunny sandy bank, tracking a 

 wasp to the entry of the nest. Having found one, sit down quietly 

 a few yards from it, and watch the wasps going in and out. Note 

 their mode of flight, in what directions they go, the number enter- 

 ing and leaving the nest within a certain time, and the effect of 

 weather on this number. In the late evening, when the wasps 

 have all returned to the nest, put over it a large sheet of coloured 

 paper in which a hole has been cut which just corresponds with 

 the entrance of the nest, pin the paper firmly down, and then be 

 out before the wasps next morning, and watch the effect on them 

 when they observe the transformation of their front door. 



After this paper has been left over the nest for several days^ 

 change it, trying the effect of different colours in succession, and 

 also the effect of transferring the last paper, after the wasps have 

 got quite used to it, to a position a yard or so away from the real 

 opening of the nest. 



Give a few wasps from the nest a feast of jam, and whilst they 

 are feeding dab some of them on the back of the abdomen with 

 distinctive bright-coloured paint, and then keep watch specially on 

 these individuals for a few days. Try and follow certain wasps as 



' See Cambridge yalural History, vol. vi. 



