THE OSMLE. 247 
bee in order to obtain her rights, and the new comer was quite 
ready for the combat. An Osmza which lives in Algiers has the 
wit to choose snail shells for its nest, and forms cells within 
them with a mixture of earth and cow-dung. Another well- 
known insect (Osmia aurulenta) seeks for the dried twigs of 
brambles, clears them out, and constructs cells inside, one after 
the other, with a small quantity of mortar. Its work is com- 
paratively easy and simpie, especially when compared with the 
labours of the Chalicodoma and other Afides. 
In the engraving the perfect insects are seen in flight, and one 
is crawling upon a leaf. The cells within the bramble are occu- 
pied by cocoons, one of which is opened to show a nymph. 
Formerly most villages and country houses were covered with 
thatch, and a stunted vegetation grew over the roofs, in which 
many insects found very comfortable homes. Many may recollect 
the pretty villages with their thatched cottages which were so 
common before slates began to be used, and many naturalists 
were aware that nearly every straw of those simple roofs was 
the cradle of many a numerous family of little bees. Now-a- 
‘days granaries and barns tell the same story, and little Osmza, 
which have long and notched mandibles, make comfortable gal- 
leries in the old straw. These insects are called Chelostomes, and 
they are so small that the inside of a straw forms a spacious 
gallery for them. Their strong mandibles are admirably adapted 
for cutting into the straw, and when this is done the inside is 
properly cleaned out, and cells are made within with the aid of 
a little mortar. It happened, therefore, in the olden time that 
the labourers inside the cottages protected and gave lodging unin- 
tentionally to hundreds of industrious and hard-working little bees. 
Some Hymenoptera which belong to the bees are leaf cutters, 
and have very long mandibles with four teeth upon them, and 
they are the instruments for perpetrating this clever piece of work. 
These bees are called J/evachilide, and the commonest species, 
which is well known in every garden, and much dreaded in green- 
houses, is Megachile centuncularis. 
It is not a remarkable looking insect; in fact no one would 
believe it to be gifted with so much intelligence by observing its 
very humble exterior. These bees are smaller than hive bees, are 
