BROOK LIFE. 163 



The Alder-blight {Field and School Work). — One 

 often finds on the trunks and branches of alders 

 growing on the margins of streams large patches of 

 snowy-white matter. These patches are composed of 

 many insects crowded together and covered with a 

 downy excretion. Such insects are known as woolly- 

 aphids. There are several kinds of common woolly- 

 aphids. That which lives on the alder is known as 

 the alder-blight, another kind living on beech trees is 

 called the beech- tree blight, and a third kind, infesting 

 apple trees, is the woolly-aphis-of-the-apple. All of 

 these secrete large quantities of honey-dew. 



Each aphid has its beak inserted into the bark of 

 the infested tree. By cutting off a section of an in- 

 fested branch and putting it in a cyanide bottle, the 

 insects can be killed, and most of them will remain 

 clinging to the branch. It can then be pinned into 

 the collection. The aphids belong to the order 

 Hemiptera ; place specimens under the following 

 label :— 



Family Aphidid.^ (iV-phid'i-dae). 



The Plant-lice or Aphids {Aph'ids). 



The Wanderer {Field and School Worh).— The 

 name wanderer has been applied 

 to a butterfly (Fig. 134) that is 

 found only in limited localities, al- 

 though it occurs from Maine to 

 Florida and westward to Kansas. 

 It prefers the borders of streams fig. i^-tTc wl^derer. 

 and marshy places where alder 

 grows ; and now that its life history is known, this 

 fact is explained. The caterpillars of nearly all but- 



