EXTERNAL ANATOMY OF INSECTS. 631 
in Cynips basilar, medial, and apical * ; and in Hylotoma 
the wing is filled with its greatest complement of areolets®. 
The medial areolets of the Intermediate Area, as you 
will see in the definitions, form ¢hree distinct series ; these 
may be called the protomesal, deuteromesal, and tritome- 
sal, reckoning from the postcostal areolets; the first of 
these corresponds with the cubital cellules of Jurine. 
These series may be expressed, according to the num- 
ber of their areolets ; by figures, the protomesal standing 
first. ‘They vary much in this respect in the different 
genera. Thus in Gyrostoma K.*, reckoning the didy- 
mous areolet as two, the numbers will stand 4:2:1; in 
Hylotoma, &c., 3:2:1%; in Aulacus, &c., 2:2:1°; in 
Bracon, &c., 2:1:1'; in Chelonus, 2:0:18; in Cynips 
erythrocephalus Jur.,.2:0:05; in Formica, 1:1:1'; in 
Oxybelus, 1:0:1*; in Chrysis, 0:1:11; and in Cynips 
Rubi K., 1:0:0™. The most natural number is 3:2: 1. 
The next in importance to the medial areolets of the In- 
termediate Area are the apical, or those open to the 
margin; the most usual number of them, excluding the 
postcostal areolets which belong to the Costal Area, is 
three ; but in Szrex there is an approach to four ® ,; in 
Evania there are only two° ; and in Philanthus there 
* Jurine Hymenopt. t. v. Gen. 40. b Tbid. t. ti. Gen. 2. 
“ This is a remarkable insect belonging to Vespa L., related to the 
hornets(V. Crabro), distinguished by having a semicircular piece taken 
out of the internal margin of each mandible, so that when these organs 
are closed there is a circular orifice,—whence the name Gyrostoma. 
* Jurine Hymenopt. t. ii. Gen. 2. * Ibid. Ord. ii. Gen. 2. 
£ Ibid. t. iii. Gen. 3. & T[bid. t. v. Gen. 41. 
h bid. t. xii. Gen. 40. i Ibid. t. v. Gen. 39. 
© Thid. t. iv. Gen. 29. 1 Tbid. t. v. Gen. 42. 
™ This Cynips inhabits a long polythalamous gall of the bramble. ° 
" Jurine Ibid. t. ii. Gen. 11. ° Ibid. Ord. ii. Gen. 1. 
