EXTERNAL ANATOMY OF INSECTS. 393 



12. Siphonuli (the Sipkonets). Truncated, fistular, seti- 

 form anal organs, emitting a saccharine fluid a . Ex. 

 Aphis. 



You will observe, that when the whole upper-side of 

 the Truncus is spoken of, it is called the Thorax; and as 

 in Coleoptera, and some other Orders, the whole of the 

 Mesothorax except the Scutellum is covered by the Tho- 

 rax, and the whole of the Metathorax by the Mesothorax 

 and Elytra — the Thoracic shield may without danger of 

 mistake be denominated the Thorax, as it has always 

 been. When the 'whole under-side of the Trunk is spo- 

 ken of, it is called the Pectus. When the three Sternums 

 are spoken of together, they may be called the Sternum • 

 and the whole interior elevation of the Pectus may be 

 called the Endosternum. 



3 De Greer ubi sUpr. t. ni.f. 5,20, 21. c. 



