52 MEMBERS OF INSECTS. 



wing, and somewhat parallel to the fore rib, runs 

 another also usually strong, sometimes the strongest 

 of all the ribs, which may be termed the mid rib ('), 

 for though not quite in the middle of the disc of the 

 wing, it is for the most part nearly so at its base. 



In many insects, particularly bees, butterflies, moths, 

 and dragon-flies, the fore and mid rib join near the 

 upper edge, at some distance from the tip, forming a 

 small opaque horny plate, probably serving as a re- 

 servoir for air or fluid, which may be termed the 

 rib-spot ( 2 ). 



From near the base in the mid rib, there is often 

 given off a branch which runs between it and the 

 fore rib, sometimes, as in butterflies, so large, that it 

 may be mistaken for the mid rib itself. It may be 

 termed the mid rib branch ( 3 ). It is wanting in bees. 



On the lower side of the mid rib several branchlets 

 are given off, which go to unite with other branchlets. 

 These branchlets may, if necessary, be numbered 

 1, 2, 3. &c., or lettered a, 5, c, &c. 



The next leading rib in the wing may be termed 

 the inner rib ( 4 ), and is usually divided near the base 

 into two, sometimes three or four, branches. In butter- 

 flies, the division takes place about the middle of the 

 wing. 



Near the under edge of the wing is another rib, 

 which may be termed the lower rib ( 5 ), between which 

 and the edge, are in some groups, one or more small 

 ribs ( 6 ). 



These several ribs and their branches, (in some 

 groups so numerous as to give the whole wing the 

 appearance of lace or net work), by inclosing portions 

 of the wing, form what may be termed areas ( 7 ), and as 



(1) In Latin, Costa media or Cubitus. 



(2) In Latin, Stigma. (3) In Latin, Costa mediastina. 



(4) In Latin, Costa interna. (5) In Latin, Costa inferior. 



(6) In Latin, Costulte marginales. (7) In Latin, Areoe. 



