CHAP. 1. 1 DEFINITION AND STI OF INSECTS. 



I i '. Principal anatomical fi 

 (Aftei Berli 

 \ \. I in. ol .li\i>i.>n bel H ind Thorax and (BB) 



between Thorax and Abdomen ; Na, Antennary Nerve; Nl, 

 Labral Nerve; Nv, Nerve-ganglia; 1". Pharynx; Gs, Supra 

 cesophageal Nerve-ganglion; Gst, Sub il Nerve- 



ganglion; Mx. Maxilla: Lb, Labium; Es, CEsopha 

 Aorta; Mes, Mid ^nt or Stomach; tl.tJ. i.'>. N^rve-ganglia 

 of thoi ii ts; al, Nei vi 



in. nt-; Mp, Malpighian Tubules ; [n, Intestim : Rt, Rectum; 

 Gn, Genital System : < >r, Genital Opening ; Vs. Dorsal Pulsat- 

 ing Vessel. may be treat- 

 ed under the heads of Nervous System, Respiratory S 

 Circulatory System. Alimentary System, and Reproductive - 



I -A 



of jointed 

 ' me af- 

 fixed to 



.1 e n t , 

 and the two 

 posterior seg- 

 ments each 

 bear in addi- 

 tion a pair 

 "I wings, 



there may al- 

 so be one or 

 more pairs ol 

 spiracle- or 

 1) r e a t h i n g 

 pores. The 

 abdomen, 

 consisting of 

 about eleven 

 s e g IU e I! t s . 



bears only 



the spiracles 



and genitalia 



as a rule, 



although in 



some forms 



there are 



t-xi e r n a 1 



a ppendages 



-j such as cerci, 



setae, forceps 



of earu igs 



and Japygids, 



etc. 

 t .in adult In 



The inter- 

 nal anatomy, 

 so far 



need be consi- 

 dered here, is 

 sufficiently 

 simple and 



