What are these small white flies and how can I identify them?

[shina]

hi friends,
I am very much excited to know about those white flies.
they are very small but much irritating. I usually went to my educational institution in morning where I could find them in large crowd. I always tried to search about it. I also googled many times but I could not recollect any specific information as I don't know its name.

 

[Greg Bernhardt]

Need more information on these "white flies" :)

Where do you live?

 

[Bystander]

"White fly" is usually reference to "mothlike" beasties on fuchsia and hanging basket type plants, or tomato, or pepper, or other annuals.
https://en.wikipedia.org/wiki/Whitefly

 

[BillTre]

There are lots of small fly-like things, for example drain flies, which can be smaller than Drosophila melanogaster (2-3 mm).
More information is needed or an ID.

You might want to catch some and look at them (probably with a magnifying glass or dissecting microscope) or photograph them (which is better, but it has to show details).
Many insects can be knocked out (undamaged dead would work too) with CO ₂ gas or cold (refrigerator or freezer). Ether and other volatile organic solvents work too but can blow up or be toxic.

If you can get a picture, you could post it here and/or do a google image search (this can lead to websites with similar pictures which might provide an ID).
Take pictures of a several flies since there could be sexual dimorphism (different forms for different sexes).

Things to note:
How many wings do they have (true flies have one pair of obvious wings, most other insects have two pair)?
Do they bite?
Is there a lot of water around or some other place the larvae may live?
Size range?
Location (geographic, type of environment, temperature)
Are they around a long time or only for short periods of time during the year?