The purpose of this paper is to give the results of a study of the wing venation in the family Aphididae with a view of replacing the arbitrary nomenclature as applied to this family by the general nomenclature of wing venation

Bartholomew, C. E.

English

University of Northern Iowa

Proceedings of the Iowa Academy of Science Volume 15 Annual Issue Article 28 1908 A Study in Wing Veination: Family Aphididae C. E. Bartholomew Copyright ©1908 Iowa Academy of Science, Inc. Follow this and additional works at: https://scholarworks.uni.edu/pias Recommended Citation Bartholomew, C. E. (1908) "A Study in Wing Veination: Family Aphididae," Proceedings of the Iowa Academy of Science, 15(1), 173-175. Available at: https://scholarworks.uni.edu/pias/vol15/iss1/28 This Research is brought to you for free and open access by the Iowa Academy of Science at UNI ScholarWorks. It has been accepted for inclusion in Proceedings of the Iowa Academy of Science by an authorized editor of UNI ScholarWorks. For more information, please contact scholarworks@uni.edu. • A STUDY IN WING VEINAT ION. Family Aphididae. BY C. E. BARTHOLO:IIEW. The purpose of this paper is to give the results of a study of the wing venation i n  the family Aphididae with a view of replacing the arbitrary nomen­clature as applied to this family by the general nomenclature of wing venation. I f  the venation of the wing as found in the more generalized Aphid ( fig. 2 )  of the subfamily Aphidinae is  compared with the arrangement of the veins of a. hypothetical wing ( fig. 1 )  it will be seen that there is little or no resemblance. If, however, the wing of the developing nymph ( fig. 3 )  i s  studied the re'Semblance i s  so close that but slight chance for mistake exists and the k.eY to the venation of the adult wing is found. I n  the wing of the young nymph the venation i s  nearly the same as in the hypothetical wing. In this case the subcostal vein ( Sc )  i·s two branclhed. The radical vein ( R )  is  four branched, branch one ( R1 )  i s not very well developed and b ranches four (R1) and five ( Re )  have coalesced. The medial vein ( M )  i s  three branched instead of four, but this loss is  common when there i s  a re­duction of this area of the wing, for instance .  as in the D iptera. The cubital vei n  ( Cu ) is normally two branched, as it is in the hypo thetical wing. There i s  but one anal vein ( A ) . In studying the wing of the mature nymph ( fig. 4 )  the venation will be seen to be the same as in the mature wing except that the coalescence of  the bases o f  the veins has not taken place. This points out the vein'S which have been lost thru coalescence and the manner in  which the reduction has taken place. The subcostal and radial areas are greatly reduced,  as is also the anal area. The medial and cubital areas re­main unreduced or  possibly increased except in the proximal portion of  the wing where all the cells have been lost. The result is that where there has been .a reduction in area there has also been a reduction in the veins by coalescence. This coalescence has taken place to such an extent that all the veins have been lost either wholly or  i n  part. The radial and subcostal veins even in the young nymph "Show a crowding together which in the older nymph have coalesced into a once branched vein, the main portion o f  which is  com11osed of the coalesced subcostal and radius, and the branch, o f  tlrn coalt'scecl branches o f  tlw radial sector. The medial vein i n  the matu re nymph is  tlrn same as i n  the young nymph. The cubital vein i s  bifu rcated nearer the .  iia"p and the anal vein lies nearer the anal margin of the wing. In the adult wing of the more general ized Aphicl ( fig. 2 )  the venation ap­pears a'S a single, much-thickened longitudin�l  vein from which arise four branch ( 173 ) 1Bartholomew: A Study in Wing Veination: Family AphididaePublished by UNI ScholarWorks, 1908174 I OWA ACADE MY O F  SCIENC E  veins, t h e  third o f  which is again branched. This thickened vein is  composed o f  t h e  subcostal , t h e  radial, except t h e  radial sector, t h e  basal portion o f  the medial, and cubital veins.  The first and second apparent branches are the sec­ond and first branches of the cubital vein re'Spectively. The third apparent branch is the medial with its three branches. The fourth apparent branch is the radial sector.  The anal vein in the adult wing remains as only a fol d  at !'· the base of the second cubital vein and forms a thickening for the attachment of the hooks o f  the caudal wing. -As specialization progres·ses in the other subfamilies of the Aphididae a re­duction of the medial vein takes place and there is first a disappearance of the branches o f  this vein and, in the most specialized wing, a complete disappear­ance of  the vein itself. In the subfamily Schizoneurinae ( fig. 5 )  the further spec ialization i s  by the coalescence of branches, one and two, of  the m edial vein which leaves this vein but two branched. In other respects the venation remains practicall y  the same as in the most generalized wing. I n  the subfamily Pemphiginae ( fig. 6) the 'Specialization has been carried still further by the coalescence of  all the branches of the medial vein into a simple vein. In the most specialized Aphid, such as is found in the subfamily Cherma­phinae ( fig. 7 ) , all trace of the medial vein is lost. There are three ways in which i t  may have disappeared. It may have coalesced with the subcostal and radial veins. I t  may have been suppre'Ssed early in its development. It  may have coalesced with the cubital vein. The coalescence of the medial vein with the subcostal and radial veins is quite doubtful as the radial sector in the wings of thi s  subfamily still retains its relationship to the radial and subcostal veins as in the other subfamilies. The entire suppression of the medial vei n  is  also quite doubtful for, while, in some of the less specialized Aphid wings there are apparent partial suppressions of this vein, such a suppression would be unusual . Wing veins do not entirely disappear in this manner. The union of the medial vein with the cubital vein I am inclined to consider as the most plausible for , in many of the more specialized wings, there is a reduction in the area be­tween the medial and cubital veins. There is also a partial coalescence- of the medial and branch one of  the cubital in the more generalized wing as i s  shown in ( fig. 4a) . This partial coalescence has probably been completed in the Cher­maphinae, and the medial and branch one of the c ubital are apparently a single vein. The study of the hind wings is more difficult than the fore wings, as they are too small and delicate to obtain mounts of. It is quite probable, however, that the condition that exists here is  the same as that in the Chermaphinae, except � that the radical sector has been lost by coalescence with the subcostal and radial veins. In the hind wing of the Chermaphiliae all the veins have coalesced into one single longitudinal vein. The following table gives the relation between the general and the -arbitrary ' nomenclature : 2Proceedings of the Iowa Academy of Science, Vol. 15 [1908], No. 1, Art. 28https://scholarworks.uni.edu/pias/vol15/iss1/28General. Subcostal ( Sc )  Radial ( R ) Radial sector ( Rs )  Medial ( M )  Medial one ( M1 ) Medial two ( M2 ) Medial three ( Ma ) Cu bi ta! one ( Cui) Cu bi ta! two ( Cu2 ) IOWA A CADE MY OF SCIENCE Cubitus Cubitus Stigma! Third Discoidal Arbitrary. Third Discoidal, first fork Third Discoidal, second fork Third Dlscoidal Second Dlscoidal First Discoidal BIBLIOGRAPHY. 1 8 9 3  Comstoclr, Evolution and Taxonomy, 1 8 9 8  Comstock ·and Needham, The wings of Insects. 1 8 9 9  Comstock and "Kellogg, Insect Anatomy. T,j 3. Fig. 1 .  Fig, 2. � .. ..  Fig. 3. Fig. 4 . Fig. 5 .  Fig. 6 .  EXLANATION OF FIGURES. Hypothetical wing, after Com stock. Wing of Macrosiphum sp. Wing of young nymph. Macrosiphum sp. Wing of older nymph. Macrosiphum SI>. Wing of Schizoneura Ianigera. Wing of Pemphigus sp. Fig, 7.  Wing of Phylloxera vnst atrix. 7 5 3Bartholomew: A Study in Wing Veination: Family AphididaePublished by UNI ScholarWorks, 1908

A Study in Wing Veination: Family Aphididae

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A Study in Wing Veination: Family Aphididae

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