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Tlio most marked changes in development are seen in butterflies, moths, flies, 

 beetles and bees. Comparatively few understand the relations existing between the 

 voracious caterpillar, the quiet brown pupa or brightly colored chrysalis, and the 

 beautiful moth or butterfly. The young caterpillar emerges from the egg and at once 

 begins feeding, casting its skin from time to time in order to allow of increase in size. 

 This, the larval stage, is the period of assimilation and growth, and it is while in this form 

 that most insects are destructive. When full grown, the caterpillar (Plate i, figure i) 

 sheds its skin and changes to a pupa, a form which is usually brownish and subconical 

 (Plate i, figures 7, 15). This transformation is frequently preceded by the spinning 

 of a cocoon (Plate I, figure 14) or by the formation of an earthen cell. During the 

 pupal stage no food is taken and only a very limited activity is possible. It is the 

 period of reorganization. From the comparatively simple caterpillar, there is de- 

 veloped the delicate moth or butterfly, which in due time emerges from the shroud- 

 like pupal case. After a time, pairing occurs, eggs are deposited and the life cycle 

 again commenced. On account of the great changes from the caterpillar through the 

 pupa to the adult, the identity of u species in the various forms can usually be 

 established only by rearing. All insects presenting such marked changes in their 

 development are said' to undergo a complete metamorphosis or transformation, a 

 change which will be found true, in endless variation, of all members of the bee, 

 beetle, fly, butterfly and moth families. 



A study of the habits of injurious insects in their various stages is the foundation 

 of applied or economic entomology, for such investigations usually reveal one or more 

 weak points in the life history of each pest that render its control comparatively easy. 



Wl)ite Aarl^cd Tussoc!<j 



A'otnli>f/uis lencostigma Abb. and Sm. 



This insect appears to thrive best in cities and villages and some seasons proves 

 a veritable scourge in certain localities. In Albany and Troy, the horsechestnuts are 

 usually partly defoliated each spring and occasionally stripped of all their leaves by 

 the voracious caterpillars of this moth. The lindens frequently suffer nearly as much, 

 and the maples and elms come in for a goodly share of attention from year to year. 

 The above is probably true to a great extent of most of the cities and larger villages 

 in the state. The summer of 1898 was marked by the abundant presence of this 

 insect, and the extensive defoliations which occurred at the time aroused the people 

 to the necessity of fighting the pest. This was done so effectively that very little 







trouble with this caterpillar was reported in 1899. 



