94 THE GYPSY MOTH APPENDIX. 



DIGESTION IX THE LARVAE OF THE 



GYPSY MOTH. 



A. H. KIRKLAND, F. J. SMITH. 



The remarkable resistance exhibited by the larvre of the 

 gypsy moth toward internal poisoning has afforded a basis 

 for the suggestion, so frequently made, that the digestive 

 functions in this insect may diifer either in character or in 

 degree from that of insects more readily killed by arsenical 

 poisons. To gain a better idea of the nature of the diges- 

 tive process in the gypsy moth larva, a limited series of 

 investigations was made in the summer of 1896 by the 

 writers, Mr. Kirkland attending to the anatomical and physi- 

 ological phases of the question, and Mr. Smith conducting 

 the chemical analyses. It was hoped at the time these inves- 

 tigations were discontinued that further study of the subject 

 could be made during the summer of 1897, but this has been 

 prevented by the demands of other work. Although but a 

 few points are established by our studies, it now seems 

 advisable to publish them as a contribution to the knowledge 

 of digestion in insects. We may properly state here our 

 belief in the importance of a thorough understanding of 

 this subject, and that whenever it is reached many obscure 

 points in the behavior of different insects toward internal 

 poisons will be cleared up. 



That the processes taking place in the alimentary canal 

 of the gypsy moth larva may be better understood, it may be 

 well to briefly consider the composition of the food consumed 

 and the anatomy of the digestive tract. 



THE FOOD OF THE GYPSY MOTH. 



In common with other Bombycid caterpillars, the larvae 

 of the gypsy moth are practically confined for food to leaves 

 of trees, shrubs or plants ; in certain rare cases this insect 



