202 HANDBOOK OF NATURE STUDY 



In order to show how many insects are destroyed by 

 birds and shrews, Professor Otto Lugger had the position 

 of five hundred chrysalides marked, on October 1, at St. 

 Anthony, Minn. Only a few insect-eating birds remain 

 in Minnesota during the winter; but these, together with 

 shrews, had reduced the original five hundred chrysalides to 

 two hundred and seventeen, by April 2. About the first of 

 April, the migratory birds return to Minnesota, and on May 

 1, only forty-three chrysalides were left. 



Some very small wasps lay their eggs into the caterpillars, 

 or the chrysalides, and the little maggots eat their host 

 alive. 



If you have observed caterpillars at all closely, you must 

 have seen that they bite off pieces of leaves, and do not 

 merely suck the juice; they can therefore be easily poisoned 

 by Paris green and London purple. A little boiled flour 

 or stale milk should be added to the liquid containing the 

 poison. These poisons cannot be used after the cabbage 

 begins to head. 



See First Annual Report of Minnesota Entomologist. 



31. The Monarch. Anosia plexippus of Comstock's 

 " Manual " ; Danais Archippus of French's " Butterflies of 

 the Eastern United States." 



MATERIAL : A sufficient number of adult insects, chrysalides, cater- 

 pillars, and eggs. Observed outdoors : Large swarms of monarchs in 

 late summer and early fall, caterpillars and eggs on milkweeds. Call 

 attention to the pollen masses often attached to the claws of butterflies. 



This is perhaps the most common and conspicuous but- 

 terfly in the Eastern and Northern states. In August and 

 September they often flock together in large swarms, and 

 thousands of them may then be found clinging to the leaves 

 of one tree. On a Sunday morning, early in September, 

 1896, the city of St. Paul swarmed with them. They came 



