Scale (insect anatomy) and enable the insect to escape. (Forsyth 1992:12) Thomas Eisner tested spiderwebs' effectiveness by dropping various insects onto the webs. Moths were consistently able to escape, and all left impact spots where scales had stuck to the web. Eisner found these spots to be common. (Eisner 2003:218-220) Scales also help increase the lift to drag ratio in gliding flight. Successive close-ups of the scales of a Peacock wing Scale (insect anatomy) The presence of scales on the wings of Lepidoptera, comprising moths and butterflies, characterises this order of insects. The name is derived from Ancient Greek λεπίδος (scale) and πτερόν
Comma category functors out of the product category formula_97. For each comma category there are forgetful functors from it. Several interesting categories have a natural definition in terms of comma categories. Limits and colimits in comma categories may be "inherited". If formula_1 and formula_2 are complete, formula_145 is a continuous, and formula_146 is another functor (not necessarily continuous), then the comma category formula_6 produced is complete , and the projection functors formula_148 and formula_149 are continuous. Similarly, if formula_1 and formula_2 are cocomplete, and formula_152 is cocontinuous, then formula_6 is cocomplete, and the projection functors are cocontinuous. For example, note that in