EXTERNAL ANATOMY OF INSECTS. 623 



have already got a tolerably good idea of these areas from 

 what has been said upon the subject under tegmina and 

 hemelytrci; but I shall now more particularly state to you 

 how they are circumstanced in wings. I shall first ex- 

 plain the general law as to their limits. The Costal 

 Area* is all that longitudinal portion of the wing that lies 

 between the anterior margin and the postcostalnervure; 

 the Intermediate Area b is all that longitudinal portion of 

 the wing that lies between the postcostal and the anal 

 nervures; and the Anal Area c is all that longitudinal 

 portion of the wing that lies between the anal nervure 

 and the posterior margin. But there are other helps to 

 enable you to distinguish the areas in the different Orders. 

 The Anal Area in all Orders forms the posterior fold of 

 the wing; in Coleoptera turned under when in repose ; in 

 Orthoptera folded like a fan; in Lepidoptera, in some 

 Papilionidde, forming an arch over the abdomen. Again, 

 mBlatta, the Costal Area is distinguished chiefly by longi- 

 tudinal nexvures ; the Intermediate by oblique ones; and 

 the Anal by radiating ones ; and in both this tribe and 

 the Mantidce this last Area is marked out from the Inter- 

 mediate by a marginal notch, which is not present in 

 Phasma, but is found in both sections of the Hemiptera. 

 In Locusta Leach the notch is between the Costal and 

 Intermediate Areas : in Phasma the nervures of the In- 

 termediate Area are branches of the externo-medial, while 

 those of the Anal, as they do in all the Orthoptera, diverge 



and Intermediate Area, are here adopted; but his Internal is changed 

 to the Anal Area, for the term internal belongs rather to the base of 

 the wing. M. Latreille afterwards relinquished both these plans, 

 N. Diet, a" Hist. Nat. i. 248- . 



* Plate X. and XXVIII. b\ i: is the Postcostal Nervure. 



b Ibid. c. re. is the Anal Nervure. ,: Ibid. d\ 



