MANUAL OF INSTRUCTIONS FOR COLLECTING AND PRE- 

 SERVING INSECTS. 



By C. V. RILEY, 



Honorary Curator of the Department of Insects, U. S. National Museum. 



CHARACTERISTICS OF INSECTS. 



The term "insect" comes from the Latin insect ton, and signifies "cut 

 into." It expresses one of the prime characteristics of this class of 

 animals, namely, that of segmentation. This feature of having the 

 body divided into rings or segments by transverse incisions is pos- 

 sessed by other large groups of animals, and was considered of suffi- 

 cient importance by Cuvier to lead him, in his system of classification, 

 to group with Insects, under the general term Articulata, Worms, Crus- 

 tacea, Spiders, and Myriopods. Worms differ from the other four groups 

 in having no articulated appendages, and in having a soft body-wall 

 or integument instead of a dense chitinous covering, and are separated 

 as a special class Vermes. The other four groups of segmented animals 

 possess in common the feature of jointed appendages and a covering of 

 chitinons plates, and are brought together under the term Arthropod a. 

 The division of the body into a series of segments by transverse incis- 

 ions, characteristic of these animals and these only, justifies the use of 

 Cuvier's old name, Articulates, as this segmented feature represents a 

 definite relationship and a natural division as much so as the verte- 

 bral column in Vertebrates. The Cuvierian name should be retained 

 as a coordinate of Vertebrates, Molluscs, etc., and the terms Vermes 

 and Arthropods maybe conveniently used to designate the two natural 

 divisions of the Articulates. 



The term "insect" has been employed by authors in two different 

 senses one to apply to the tracheated animals or those that breathe 

 through a system of air tubes (tracheae), comprising Spiders, Myriopods, 

 and insects proper or Hexapods,* and the other in its restricted sense 

 as applied to the Hexapods only. To avoid confusion, the latter signifi- 

 cation only should be used, and it will be thus used in this article. 



*Frorn the Greek ^dnovc, having 6 t'ccf. 



