ⓘ Comstock–Needham system. The Comstock–Needham system is a naming system for insect wing veins, devised by John Comstock and George Needham in 1898. It was an im ..

                                     

ⓘ Comstock–Needham system

The Comstock–Needham system is a naming system for insect wing veins, devised by John Comstock and George Needham in 1898. It was an important step in showing the homology of all insect wings. This system was based on Needhams pretracheation theory that was later discredited by Frederic Charles Fraser in 1938.

                                     

1.1. Vein terminology Longitudinal veins

The Comstock and Needham system attributes different names to the veins on an insects wing. From the anterior leading edge of the wing towards the posterior rear, the major longitudinal veins are named:

  • radius R, in analogy with a bone in the forearm, the radius
  • anal veins A, in reference to its posterior location
  • cubitus Cu, meaning elbow
  • media M, meaning middle
  • subcosta Sc, meaning below the rib
  • costa C, meaning rib

Apart from the costal and the anal veins, each vein can be branched, in which case the branches are numbered from anterior to posterior. For example, the two branches of the subcostal vein will be called Sc 1 and Sc 2.

The radius typically branches once near the base, producing anteriorly the R 1 and posteriorly the radial sector Rs. The radial sector may fork twice.

The media may also fork twice, therefore having four branches reaching the wing margin.

According to the Comstock–Needham system, the cubitus forks once, producing the cubital veins Cu 1 and Cu 2. According to some other authorities, Cu 1 may fork again, producing the Cu 1a and Cu 1b.

As there are several anal veins, they are called A1, A2, and so on. They are usually unforked.

                                     

1.2. Vein terminology Crossveins

Crossveins link the longitudinal veins, and are named accordingly for example, the medio-cubital crossvein is termed m-cu. Some crossveins have their own name, like the humeral crossvein h and the sectoral crossvein s.

                                     

2. Cell terminology

The cells are named after the vein on the anterior side; for instance, the cell between Sc 2 and R 1 is called Sc 2.

In the case where two cells are separated by a crossvein but have the same anterior longitudinal vein, they should have the same name. To avoid this, they are attributed a number. For example, the R 1 cell is divided in two by the radial cross vein: the basal cell is termed "first R 1 ", and the distal cell "second R 1 ".

If a cell is bordered anteriorly by a forking vein, such as R 2 and R 3, the cell is named after the distal vein, in this case R 3.

                                     
  • James George Needham March 16, 1868 in Virginia, Illinois July 24, 1957 was an American entomologist After studying with John Henry Comstock at Cornell
  • co - proposer of the Comstock - Needham system with James George Needham In 1893, John Henry Comstock and Simon Henry Gage founded the Comstock Publishing Company
  • prison warden John Henry Comstock 1849 1931 U.S. entomologist, co - creator of the Comstock - Needham system Keith Comstock born 1955 major league
  • surface of the rib Cauto vein, a type of insect wing segment in the Comstock Needham system Costa disambiguation Costas disambiguation Coastal Intercostal
  • species have long oval forewings with very few cross veins see Comstock - Needham system but the hindwings are usually very small or even absent. The males
  • This family is closely related to Pseudocaeciliidae. Insect wing Comstock - Needham system Lienhard, C. Smithers, C. N. 2002. Psocoptera Insecta World
  • produce a work of art Media, a group of insect wing veins in the Comstock - Needham system Growth medium, objects in which microorganisms or cells can experience
  • fossil data and speculation. The Comstock - Needham system designed by entomologists John Henry Comstock and George Needham describes these veins and their
  • pterostigma that is oval in shape. The Rs vein, as designated by the Comstock Needham system is shorter than the connected R2 3 4 Heinrichs, J Schmidt, AR
  • pterostigma that is oval in shape. The D cell, as designated by the Comstock Needham system is notably elongated and narrowed, in comparison to all other