190 



THE MAKVEL OF INSECT LIFE. 



much excavation between. Some of the Osmia bees are 

 very small, and burrow into the pith of broken or cut 

 twigs. If the ends of some cut branches of a rose, a 

 bramble, or a jessamine be examined, some of them will 

 be found to have a little round hole in the pith scarcely 

 large enough to admit a No. 5 shot. If such twigs be 

 cut longitudinally, they will be seen to contain a row of 

 little oblong cells, from which in process of time will be 

 developed tiny blackish bees. Several insects have this 



Fig. 1. OSMIA BURROWS. Fig. 2. MEGACH1LE BURROW. 



habit, but that which is most commonly found in twigs 

 is Osmia leiicomelana. 



The number of cells is very variable. Sometimes 

 there are six or seven, but in a specimen now before me 

 there are only three. The bee, however, seems to have 

 met some impediment in her work. She has begun, as 

 usual, in the centre of the pith, but, instead of keeping 

 to the middle, she has gone off obliquely until she came 

 against the wood. Then she has gone downwards for a 

 little distance between the wood and the pith, and 

 probably has disliked the direction of the burrow, 



