3700 Insects. 



larger, and consisted also of worker-cells : the third comb, in the centre 

 was occupied with cells of males, whilst those towards its sides were 

 rather larger, and contained females : below this comb was another, 

 jnst commenced, and consisting of worker-cells alone. On giving the 

 wasps their liberty, many of them, after visiting the dissolved sugar, 

 re-entered the nest, and hurried over the cells of the males and fe- 

 males to those of the workers, which latter they fed very assiduously, 

 but I observed that it was only those wasps which had flown to a dis- 

 tance that fed the male and female grubs. To satisfy myself more 

 fully on this point, I closed the entrance when all the wasps were in 

 the nest at night, and placing sugar and water in the box, I watched 

 with great attention all their proceedings ; still, none fed the males 

 and females, but continued their attention to the workers. On again 

 giving them their liberty, T found as before that those wasps alone fed 

 the males and females which had flown to a distance in search of a 

 more suitable nourishment. This will, I think, account for the habit 

 of wasps in killing other insects, and at times collecting animal juices, 

 such being, in all probability, the suitable nutriment for grubs of the 

 males and females. 



When the grubs are fully fed, they spin or rather line the cell with 

 a thin silken covering, closing the top with one of a much thicker con- 

 sistency. These shrouds, in which the grubs are inclosed, are easily 

 extracted from the cells of V. Norwegica, being in them much thicker 

 than in those of V. rufa, and of a nearly uniform thickness throughout; 

 those of the latter are extremely thin and delicate below the cap of 

 the cell, which, however, is continued of the same thickness for about 

 a quarter of an inch within the cell. I frequently watched the grubs 

 while constructing the caps of the cells, which appears to be a process 

 effected in a few hours. 



I have stated above that the nest of V. rufa contained four combs ; 

 the cells in the fourth were in progress, not being more than from one 

 to two eighths of an inch deep : each contained either an egg or a mi- 

 nute larva, so that in the first instance, or at the commencement of a 

 colony, time is saved by these means, the building of the cells pro- 

 gressing with the growth of the larvae. And this alone can be the ob- 

 ject, as immediately on a wasp emerging from its cocoon, the workers 

 first chip off with their mandibles the remains of the cell-cap, and 

 then clean out the cell for the occupation of another inhabitant. 



In the construction of their cells the tree-wasps may be regarded as 

 card-board makers, and the ground-wasps — V. rufa, V. Germanica, 

 and V. vulgaris — as paper-makers. The cells of the tree-wasps are 



