SQENTIFIC SURVEY. 



151 



served as a passage to several cells, in each of which a little ball 

 of pollen was formed, and a single egg deposited thereon ; the 

 larvae were usually ten or twelve days consuming it, by which 

 time they were fully fed ; in this state they lay until they changed 

 to the pupa-state, when they very shortly became matured.' I 

 have reared individuals of H. rubicundus from the egg to the per- 

 fect insect; on the 15th of July I procured cells containing the 

 pollen balls, with an egg dn each ; in twelve days the larvae were 

 full-fed : the change to the pupa-state took place about the 25th of 

 August, and during the first week of September the perfect state 

 was acquired. The history of Ealictus, therefore, is as follows : 

 the males and females appear in the autumn ; the latter being im- 

 pregnated, pass the winter in the perfect state, appearing during 

 the following season to perform their economy, as detailed above 

 in the case of ^. morio.^' 



All these females of solitary species are found in spring on the 

 blossoms of fruit trees, of wild cherries and about flowers. 



Vespidae, (wasps, yellow-jackets.) The hornet is the Vespa cra- 

 bro of Europe. The group is characterized by the folding of the 

 wings, longitudinally. Vespa lives in colonies of three kinds of 

 individuals, constructing complex nests either under ground or 

 attached to the branches of trees, consisting of several galleries of 

 hexagonal cells, with their mouths downward, connected and sup- 

 ported by pedicels, and surrounded by an outer papery envelop. 

 The females which have survived the winter begin in the spring to 

 form their small nests, consisting of a single tier of a few cells, in 

 which they lay their eggs and feed the young workers. The males 

 and females do not appear until autumn. Reaumur has observed 

 that there are two sizes among the males. 



" Notwithstanding the powerful sting of the wasp, it is liable to 

 the attacks of other insects. EMpiphorus paradoxus and the larva 

 of a Volucella infests its nests, de\ curing the larva ; as does also 

 Anomalon vesparum, and another species of Ichneumon. Dr. Leach 

 also mentions that wasps are much infested by Lebia linearu. I 

 have also observed a spider sucking a wasp, which it had killed." 

 — Westwood. 



Wasps should, if possible, be collected by the whole colony, 

 when the individual variation of the three kinds of individuals— the 

 males, females and workers — can be studied. For this purpose 

 visit the nests by night, plug up the hole with a sponge saturated 



