112 NATURE STUDY REVIEW [10:3— Mar., 1914 



Cabbage plants and brussels sprouts afforded a rich field for 

 investigation. The students were asked to bring in leaves with 

 cabbage worms on them, to find out how these insects eat, how they 

 move about and the number and arrangement of their feet. 



The cabbage worms were brought in, but more than these. 

 Some of the students brought leaves covered with aphids. Some 

 of them had discovered that there were two kinds of "worms" or 

 larvae, on the cabbage. These were examined in class and the 

 differences noted. The largest individual of each species were 

 placed in boxes and in less than a week we had the pupae, the 

 angular chrysalid, of the cabbage butterfly and the thin cocoon 

 with the dark pupa of the cabbage moth. 



"What is the difference between a moth and a butterfly," was 

 asked ? The question was answered in part by looking at mounted 

 specimens of moths and butterflies. 



Some eggs of the cabbage butterfly were found. The butterflies 

 themselves were captured and studied ; so we had all the stages in 

 the life history of an insect having complete metamorphosis. This 

 work was followed by a library lesson in which the students looked 

 up methods of combating these insects. 



The characteristics of the cabbage aphids, the type of moth, 

 the kind of metamorphosis, etc., were discovered with little diffi- 

 culty. A search for aphids on other plants was begun. Willow twigs 

 were brought in covered with the insects, some winged individuals, 

 some wingless, some true females and males. The white pine twigs 

 showed not only all the different kinds of aphids but also the 

 regular rows of eggs on the needles. 



The most interesting study, however, was found on wild lettuce. 



Here was a real insect community, not only aphids, but two 

 species of lady bird beetles, both the young and the adult, several 

 ants, and two larvae of syrphus flies. It did not take long to discover 

 that the lady birds and syrphus larvae were intent upon devouring 

 the aphids, while the ants were feeding upon honey dew. 



The lesson was followed by a study of the corn-root aphis, a 

 very distructive pest in Illinois. The story of the life history with 

 the relation of the small field ant to the aphis, and methods used 

 in combating the insects were obtained from library references. 



The ladybird beetles introduced us to a series of lessons on 

 beneficial insects. We first studied predaceous types, ladybirds, 

 lace wing flies, dragon flies, searcher beetles, robber flies, water 

 beetle and hornets. In the meantime some one had brought into 



