632 EXTERNAL ANATOMY OF INSECTS. 



Intermediate Area of these wings into three portions, the 

 basal, medial, and apical*, I have endeavoured to re- 

 medy this defect, and by naming each set of areolets in 

 the middle portion, as you will see in the Orismological 

 Definitions, under the term Areolets, you will find it 

 easy to describe any given areolet and its place in the 

 wing ; those of the base may be called the anterior, in- 

 termediate, and poster ior, where three occur; and the first 

 and last of these terms will suffice where there are only 

 two : the apical areolets, or those that are open to the 

 margin, may be called, first, second, and third, in the 

 order of their occurrence, reckoning from the anterior or 

 costal margin. 



In this Order it is curious to trace the progress of neu- 

 ration in the wings of different genera. Thus in Psilu s 

 only the costal nervure and the stigma are to be traced b ; 

 in Chalets the postcostal and stigma c ; in Codrus and JLeu- 

 cospis the costal, postcostal, stigma, and a nervure repre- 

 senting the externo-medial and interno-medial coalescing 

 into one d ; in Omalus the basilar areolets appear e ; in 

 Crabro both basilar and medial f ; in Cynips basilar, 

 medial, and apical*; and in Hylotoma the wing is filled 

 with its greatest complement of areolets h . The medial 

 areolets of the Intermediate Area, as you will see in the 

 definitions, form three distinct series; these maybe called 

 the protomesal, deuteromesal, and tritomesal, reckoning 

 from the postcostal areolets; the first of these corresponds 

 with the cubital cellules of Jurine. These series may be 



2 Plate X. Fig. 8. basal e\ medial/-, apical g\ 



b Jurine Ifymenopt. t. v. Gen. 48. '■ Ibid. Gen. 4/. 



rf Ibid. Gen. 45, 46. Comp. Plate X. Fig. 1 1. 



e Jurine Ibid. Gen. 43. f Hid. t. iv. Gen. 47. 



6 Ibid., t. v. Gen. 40. h Ibld _ { „ Gen % 



