354 Annals Entomological Society of America [Vol. XI, 



fold which overlaps it, and the postscutellum also bears a 

 phragma or internal transverse process for the attachment of 

 the longitudinal muscles arching the notum in the movements 

 of flight. 



Along the sides of the ?iotum, or tergal region of the segment, 

 are several projections, some of which are involved in the 

 movements of flight. The anterior projection "pao" or prealare, 

 sometimes forms a complete pre-alar bridge extending in front 

 of the wing from the tergal region to the pleural region, and in 

 some insects it extends down to, or slightly beyond, the pleural 

 plate "ba" of Fig. 3, {i. e., the anterior one of the two plates 

 labeled "ba2" in Fig. 1). The projecting region "sur2" (Fig. 3) 

 or suralare is frequently demarked by a complete suture, and 

 it serves as an anterior pivot for the wing, in the movements of 

 flight. Certain of the other projections also serve as pivots for 

 the wing in the movements of flight, but are of no great 

 morphological importance. 



The Wing-Ossicles. 



At the bases of the wing veins are several small articulatory 

 plates called alar ossicles, which assist in the articulation of the 

 wings to the tergal region. There are also some small plates 

 below the wing near its attachment to the body, and these are 

 also included under the designation alar or wing ossicles. The 

 alar ossicles by means of which the wing articulates with the 

 tergal region or notum, are called pteralia. 



A small plate called the tegiila 'Hg" (Fig. 3) occurs near the 

 anterior margin of the wing, at its base, and might be included 

 with the alar ossicles. The principal alar ossicle, however, is 

 the notopterale "np2," which seems to be a detached portion of 

 the tergal region which doubtless originally projected from its 

 lateral margin somewhat after the fashion of the sclerite "sur." 

 In its typical form, this ossicle bears an anterior neck-like nar- 

 row region articulating with the base of the vein called the 

 subcosta in Comstock's terminology. Beside the ossicle "np" 

 is a more or less distinct ossicle "m," which is formed at the 

 bases of certain of the wing veins. The radius, media and 

 cubitus of Comstock's terminology may extend to it, although 

 a chitinized area may intervene between it and the bases of 

 certain of these veins. The sclerite "m" has been termed the 

 medipterale, or the middle one of the pteralia. The ossicle "b" 



