INSECTS. 119 



than males among those that appear in the autumn and winter, 

 and that the males are most abundant in the spring. The slug- 

 gish females instinctively make their way towards the nearest trees, 

 and creep slowly up their trunks. In a few days afterwards they 

 are followed by the winged and active males, which flutter about 

 and accompany them in their ascent, during which the insects pair. 

 Soon after this, the females lay their eggs upon the branches of the 

 trees, placing them on their ends, close together in rows, forming 

 clusters of from sixty to one hundred eggs or more, which is the 

 number usually laid by each female. The eggs are glued to each 

 other, and to the bark, by a grayish varnish, which is impervious 

 to water ; and the clusters are thus securely fastened in the forks 

 of the small branches, or close to the young twigs and buds. Im- 

 mediately after the insects have thus provided for a succession of 

 their kind, they begin to languish, and soon die. The eggs are 

 usually hatched between the first and the middle of May, or about 

 the time that the red currant is in blossom, and the young leaves 

 of the apple-tree begin to start from the bud and grow. The little 

 canker-worms, upon making their escape from the eggs, gather 

 upon the tender leaves, and, on the occurreHce of cold and wet 

 weather, creep for shelter into the bosom of the bud, or into the 

 flowers, when the latter appear. Where these insects prevail, they 

 are most abundant on apple and elm trees ; but cherry, plum, 

 and lime trees, and some other cultivated and native trees, as well 

 as many shrubs, often suffer severely from their voracity. The leaves 

 first attacked will be found pierced with small holes ; these become 

 larger and more irregular when the canker-worms increase in size ; 

 and, at last, the latter eat nearly all the pulpy parts of the leaves, 

 leaving little more than the midrib and veins. A very great dif- 

 ference of color is observable among canker-worms of different ages, 

 and even among those of the same age and size. It is possible that 

 some of these variations may arise from a difference of species ; but 

 it is also true that the some species varies much in color. When 

 very young, they have two minute warts on the top of the last 

 ring ; and they are generally of a blackish or dusky brown color, 

 with a yellowish stripe on each side of the body ; there are two 

 whitish bands across the head ; and the belly is also whitish. When 

 fully grown, these individuals become ash-colored on the back, and 

 bla2k on the sides, below which the pale yellowish line .'remains. 

 Some are found of a dull greenish yellow and others of a clay color, 

 with slender interrupted blackish lines on the sides, and small spots 



