Skipper (butterfly)

The skippers are a family of butterflies, the Hesperiidae. They are named after their quick, darting flight. 

Skippers used to be classified in their own superfamily, Hesperioidea, because they have their antennae clubs hooked backward like a crochet while the other butterflies have club-like tips to their antennae. Skippers also have generally stockier bodies than regular butterflies, with stronger wing muscles. Brower, Andrew V.Z. & Warren, Andrew (April 7, 2008). "Hesperiidae" . Tree of Life Web Project. Retrieved December 24, 2009.

 Subfamilies 
There are about 3500 species of skippers.Ackery P.R; de Jong R. & Vane-Wright R.I. 1999. "The Butterflies: Hedyloidea, Hesperioidea and Papilionoidae". In: Kristensen N.P. (ed) Handbook of Zoology: A Natural History of the Phyla of the Animal Kingdom. Volume IV Arthropoda: Insecta, Part 35: Lepidoptera, Moths and Butterflies Vol.1: Evolution, Systematics, and Biogeography: 263–300. Walter de Gruyter, Berlin, New York.  They are usually classified in the following subfamilies:
 Coeliadinae: awls, awlets and policeman (butterfly) (about 75 species)
 Hesperiinae: grass skippers (over 2000 species)
 Heteropterinae: skipperlings (about 150 species)
 Megathyminae: giant skippers (about 100 species)
 Pyrginae: spread-winged skippers (about 1000 species)
 Pyrrhopyginae: firetips (about 150 species)
 Trapezitinae: Australian skippers (about 60 species)

Many species of skippers look frustratingly alike. For example, some species in the genera Erynnis, Hesperia, and Amblyscirtes cannot currently be distinguished in the field even by experts. The only reliable method of telling them apart involving dissection and examination of the genitalia.

Examples
Examples include:
Aaron's skipper - Poanes aaroni
Chequered skipper - Carterocephalus palaemon
Small skipper - Thymelicus sylvestris
Essex skipper - Thymelicus lineola
Lulworth skipper - Thymelicus acteon
Silver-spotted skipper - Hesperia comma
Large skipper - Ochlodes venata
Dingy skipper - Erynnis tages
Grizzled skipper - Pyrgus malvae
Dakota skipper - Hesperia dacotae

References

Other websites
Skippers of North America: Large format diagnostic photographs Cirrus Digital Imaging
 Tree of Life Hesperiidae