166 FOREST ENTOMOLOGY. 



beg to give at considerable length some of bis " notes," together with 

 his illustrations, as I know of nothing more helpful to the student 

 who wishes to make a thorough study of the insects in question. 



"The head is nearly always broader than long, and generally about 

 the same breadth as the thorax. The eyes are large, and ocelli are also 

 present. Behind the ocelli there is a quadrangular space, bounded 

 latterly by distinct furrows, known as the vertical area. The spaces 

 bordering the compound eyes are the orbits. The space containing the 

 ocelli, and reaching to the insertions of the antenna?, is the frons, and 

 part of this space surrounded by furrows is called the pentagonal area. 



" Looking at the face and below the antenna? we see the clypeus 

 and labrum. The space between the eye and base of the mandible 

 is termed the gena. 



" The back of the head, facing the thorax, is the occiput. Between 

 the occiput and the compound eye lie the tempora. 



" The details of the thorax, which furnish many very important 

 characters, can hardly be made clear except by diagrams. I give 

 therefore now an outline camera -lucida sketch of the thorax in 

 Tenthredo mesomela, L., viewed from two aspects (fig. 157) dorsally, 

 i.e., from above ; (fig. 158) laterally, i.e., from the side : 



a (in both figures), pronotum. (the central slit in this is 



bb, tegulse. what Cameron calls the 



r, middle (or front) lobe of meso- blotch). 



notum. hh, cenchri (the space between 



dd, side lobes of mesonotum. them is the metanotum). 



e, scutellum (or better, perhaps, k (in fig. 158), prosternum. 



scutellum mesothoracis, to I, mesosternum. 



distinguish it from /). m, metasternum. 



/, postscutellum (better scutellum n, mesopleura. 



metathoracis). o, metapleura. 



g, propodeum or median segment PPP, coxee. 



"Note. The unlettered areas in fig. 157 are parts of the meso- and 

 meta-thorax, which are seldom, if ever, referred to in descriptions, and 

 I therefore ignore them. The shaded space indicates a very deep 

 impression between the meso- and meta-thoracic regions. 

 "I may add that 



the pro-thorax includes the areas a and k ; 



the meso-thorax includes the areas c, d, and e in fig 157; n and I 

 in fig. 158 ; 



