220 MANUAL OF NATURAL HISTORY. 



especially numerous in tropical regions, while, in our 

 own country, we may reckon three thousand species. 



It is among the hymenopterous tribes that we 

 find those remarkable social communities, where the 

 workers consist of abortive females, where the idle 

 drones are the males, and where one chosen female 

 is elected queen, and made the prolific mother of an 

 entire generation. The nectar of flowers is the fa- 

 vourite drink of these active, bustling, tribes in their 

 perfect state ; but when we see the busy Bees intent 

 upon fresh-blown flowers, we must not imagine the 

 luscious banquet spread for themselves alone, it is 

 for the young of the community, yet unborn, that 

 they labour to collect the honey and the pollen. In 

 the same manner, when we spy out a robber wasp 

 dragging away the dead carcase of a fly bigger than 

 herself, it is for the sustenance of her future progeny 

 that the deed of poisoning was done. The Aphidian 

 cows kept by Ants, and watched with so jealous a 

 care, are valued only for the honey- dew they yield, 

 and with which they nourish their young ones. 



Belonging to this Order we find the Saw-Flies, 

 which make incisions into the leaves and stems of 

 plants, by means of elaborately-formed saws, placed 

 at the end of their bodies, and the larvse of some 

 species of which live in societies covered over with 

 a tent of leaves, fastened together by silk. The Gail- 

 Flies are another remarkable race, which puncture 

 the surface of plants, by means of a boring instru- 

 ment, and, by depositing their eggs in the punctures, 

 produce " galls" of various kinds ; to the " gall" pro- 



