70 ENTOMOLOGICAL NEWS. [May, 



ELEMENTARY ENTOMOLOGY. 



FIRST PAPER— WHAT IS AN INSECT? 



While the study of Entomology, or the knowledge of Insects, 

 is one of the most fascinating of pursuits, it is not a matter of 

 wonder that many have been deterred from undertaking it, be- 

 cause of the difficulties with which it is hedged about, and the 

 array of strange, technical words with which it is surrounded. 

 The purpose of these articles is, therefore, to endeavor to popu- 

 larize the study by explaining, in as simple a manner as possible, 

 the various technical terms which, of necessity, must be employed 

 by scientific writers. 



The word Insect is, as a rule, very loosely employed by those 

 who have not studied the subject. Even scientific usage of the 

 word has varied, and Insects are sometimes regarded as equiva- 

 lent to the group described later oh in this paper under the name 

 of Tracheata. In this series the word Insect is used in a restricted 

 sense, and does not include such animals as spiders, centipedes 

 and mites, and yet we would not exclude from the pages of this 

 journal information about such creatures, since we hope to give 

 our readers some very interesting notes on spiders (as well as on 

 ants), from the pen of our fellow-member, the Rev. Dr. McCook, 

 who has made the study of their habits a specialty, and who 

 knows so well how to interest his readers. 



Insects may be described as being (i) joint-footed animals, 

 breathing by tracheae; (2) having the body of the adult divided 

 into three distinct portions, — head, thorax and abdomen; (3) 

 having in the perfect or imago state, one pair of antennae attached 

 to the head. 



(i) The joint-footed animals, or technically the Arthropoda 

 (which is the Greek equivalent), are formed on a diflferent plan 

 from the other branches of the animal kingdom. Their bodies 

 are composed of a series of rings (or segments), within which are 

 the vital apparatus and muscles. It is true that many of the 

 Worms have their bodies segmented, but no Worms have jointed 

 feet. A vast number of animals are included within the Arthro- 

 poda, — not only the Insecta, but also the Arachnida (spiders, 

 scorpions, etc.), the Myriapoda (centipedes, millipedes, etc.), 

 certain curious animals known as Onyckophora, and the Crustacea 



