136 Invertebrata. 



a. With suctorial mouths, wings absent, or 



when present having the fore pair 

 thickened. Order Rhynchota. 

 Wings four equal, membranous. Order 

 Thysanoptera. 



b. With masticatory mouths, abdomen with 



a terminal appendix of bristles or a 



bifid tail. No wings. Order Thysanura. 



Abdomen with a terminal two-bladed 



forceps. Order Euplexoptera. 

 Abdomen ^syith no appendages, wings with 



reticulated costse. Order Orthoptera. 

 B. Insects which pass through a quiescent pupa stage. 



a. Mouth masticatory; wings membranous, 



equal. Order Neuroptera. 



Wings hair-clad or scaly, unequal. 

 Order Trichoptera. 



Fore- wings converted into hard wing- 

 covers, Order Coleoptera. 



b. Mouth suctorial; with rudimental wings 



and compressed bodies. Order Aphan- 



iptera. 



With two wings. Order Diptera. 

 With four wings, the anterior short, 



twisted. Order Strepsiptera. 

 Wings large and scale-covered. Order 



Lepidoptera. 

 Wings naked, membranous, few-veined 



Order Hymenoptera. 



