3 tO ORISMOLOGY. 



by the shield of the prothorax. Ex. Hymeno- 

 ptera. 



2. COVERED ( Tectum). When it is quite concealed by 



the prothorax. 



3. AREATE (Areatum). When it is larger than the 



prothorax, and terminates towards the wings in 

 two oblique areas, mclosed by a ridge often crown- 

 ed anteriorly with little teeth. Ex. Libellulina. 

 PLATE IX. FIG. ?.,. N.B. The space between 

 these areas isjitted with a membrane capable of ten- 

 sion and relaxation, which in Jlight causes them to 

 approach to and recede from each other. 



4. AMPLECTENT (Amplectens). W T hen posteriorly it is 



so curved as to form a large sinus which embraces 

 the dorsolum. Ex. Vespa L. PLATE IX. FIG. 

 11. g: 



5. PHONETIC (Phoneticum}. When its posterior an- 



gles, approaching the wings, cover the vocal spira- 

 cles 3 . Ex. Hymenoptera. 



/3. DORSOLUM. 



1. THORACIFORM ( Thoraciforme}. When it forms 

 the principal part of the upper surface of the 

 trunk. Ex. Bombus, Apis, Vespa &c. PLATE IX. 

 FIG. 11. i: 



y. SCUTELLUM. 



1. DISTINCT (Distinctum}. When it is separated from 



the dorsolum by a suture. Ex. Hymenoptera, 

 Diptera. PLATE IX. FIG. 11, 19, &c. '. 



2. COALITE (Coalitum). When it is not separated 



a Chabrier Sur le Vol des Insectes. Mem. du Mus. /. viii. 55. 



