CHAPTER II. 



Use of scientific terms common and necessary, 27, 28. Reasons why an outline of 

 entomological classification and nomenclature is necessary, 28, 29. Importance 

 of Entomology, 30, 31. Reasons why the study of insects has not been popu- 

 lar, 33, 34. Definition of insects, 36. Changes which they undergo, 37. 

 Breathing organs of insects, 38. Systematic arrangement of, 39. Definition, 

 40. Scheme, 40. Order I., Coleoptera, 41. Order II., Orthoptera, 47. Order 

 III., Neuroptera, 48 Order IV., Hymenoptera, 49 Order V., Trichoptery, 50. 

 Order VI., Strepsiptera, 51 Order VII., Hemiptera, 52 Chinch Bug, 52. 

 Aphidse in the United States, 53 Order VIII., Depidoptera, 54. Order IX., 

 Diptera, 56. Technical characters of the Cecidomyia, the genus to which the 

 wheat midge belongs, 56. Order X., Aphaniptera, 57. Order XI., Thysanoura, 

 58 Order XII., Parasita, 59. 



27. Every agricultural publication contains from time to time 

 descriptions of insect depredators, in which are frequently em- 

 ployed many of the scientific terms used by entomologists to de- 

 signate the species, genus and order, to which the maurauder be- 

 longs. The use of some scientific terms is very often absolutely 

 necessary in giving even a popular description of a fly, a beetle, 

 a weevil, a parasite, or a so called bug. 



28. Every one is familiar with the frequent occurrence of such 

 terms as coleopterous insect, dipterous insect, parasitical insect, 

 larva, pupa, &c. Farmers ought to be familiar with these terms, 

 and to be able to form a correct idea of the nature of an insect 

 depredator, which may occasion injury or alarm, whether they 

 acquire their information from the perusal of a popular but suffi- 

 ciently accurate description, or whether they seek to convey in 

 written words an account of what they observe with such ac- 

 curacy and distinctness as would enable any one acquainted with 



