The Humming Bird. 39 



others are tubes open at one end only, and corked tightly 

 with plugs of cotton. Each of these contains insects of some 

 kind in process of development, though just now most of 

 them are torpid, passing the winter in the chrysalis. 



For example, in one jar are two gr three sunflower heads 

 which were infested by the larvae of the beetle.. The little 

 worms have buried themselves in the sand with which the 

 vessel is half filled, and next spring they will emerge as 

 perfect beetles, ready to lay their eggs in fresh sunflowers. 



By thus confining an insect where it can be watched its 

 life history may be studied at leisure. All its transformations 

 may be noted, the breeding being carried on with many species 

 or generation after generation. 



In a small jar half full of beans there are hundreds of 

 bean-eating bugs which will continue to reproduce their kind 

 so long as the food supply holds out. 



Most of the jars are covered with muslin gauze, so as to 

 admit the air w r hile others are closed with glass tops to retain 

 moisture. 



In one jelly glass filled with little flies is an Irish potatoe 

 riddled with holes by the maggot-like larvae of the flies. A 

 jar contains a few twigs infested with little worms which will 

 come out after a while as beetles. In another receptacle, 

 half full of sand, are some yucca pods lying about. 



They have been abandoned by certain grubs, which have 

 buried themselves in the sand, where they will undergo a 

 transformation, emerging next spring at the blossoming time 

 •of the yucca in the shape of white moths. Yet another vessel 

 holds half a dozen huge oak galls, three inches in diameter. 



They are tumoury-like excrescences caused by small gnat- 

 like insects, which sting the stem of the plant in hundreds of 

 places close together, depositing an egg in each wound. 



Thus irritated, the tree forms over the injured part an 

 odd-looking growth, which serves to protect the offspring of 

 the gall bag until they are ready to go out into the world and 

 lay more eggs, perhaps on the stem which fostered them. 

 Some galls are woolly and others are of brilliant colours. 

 They have many commercial and medicinal uses. 



Every day all of the glass receptacles are examined. 

 Newly hatched insects, when wanted, are removed and killed, 

 after which they are stuck on pins in boxes, arranged accord- 

 ing to species, as books are arranged in a library. The boxes 

 shaped like hollow books and opening in the same way, are 

 similarly placed in rows on shelves, the back of each one 

 labelled. 



