156 HOME STUDIES IN NATURE. 



conducted, I will state that I had a tub of water in 

 which were growing the various species of utricularia. 

 When I wished to experiment with any particular spe- 

 cies, I took such species from the tub and placed it in 

 a small vessel of clear water. I also had other tubs of 

 water for the purpose of securing the eggs of the mos- 

 quito and chironomus. The eggs of the mosquito are 

 deposited in large clusters, which float on the surface 

 of the water. Those of the chironomus are deposited 

 in a jelly mass of matter, and fastened by a little thread 

 to something to prevent them from sinking too low in 

 the water. These masses of eggs are very conspicuous 

 to the educated eye, one species producing a mass as 

 large as a good-sized pea ; the jelly is quite transparent, 

 so the eggs can be distinctly seen with the naked eye. 

 After they are hatched, the young chironomus larvae 

 remain in the jelly for a day or two, feeding on it until 

 they are large and strong enough to venture out into 

 the great world of water, where they can secure their 

 own livelihood. 



It can be seen how quickly and easily I could swarm 

 a small vessel of water with the larvge of the mosquito 

 and chironomus by transferring to the vessel these 

 masses of eggs. After this long but necessary digres- 

 sion I will return to the valve of the utricularia. 



Mr. Darwin says (" Insectivorous Plants," p. 407) : 

 " To ascertain whether the valves were endowed with 

 irritability, the surfaces of several were scratched with 

 a needle or brushed with a fine camel's-hair brush, so 



