Keys for the identification of British Diptera

Welcome to my selection of illustrated identification aids for insects. The amazing diversity of insects illustrates and celebrates the creativity and imagination of God and my hope is that you will not only find these keys useful and attractive but also that they would lead you to worship.

These dichotomous keys are designed for use on screen. I would like to envisage them being used on a PC at home or in a lab, or used in the field, for example on a smart phone or tablet. They are not designed to be printed. The layout with one couplet for each page is deliberate and moving through the keys should be possible using the hyperlinks, or if using a tablet, by swiping through the document.

It is my conviction that good quality keys should be available online for all users freely so that advances in natural history knowledge are not hampered at the first hurdle of identification.

If you find the keys helpful please let me know. I am very keen to improve them so if you find anything that needs changing, is unclear, or requires clarification please contact me on

I am also a keen botanist and am trying to write illustrated keys for the plants of North Hampshire in southern England. Follow the blog at http://mikehackston.blogspot.co.uk where notifications of any updates to keys will be posted.

For keys to Hymenoptera and other insect orders - go to https://sites.google.com/site/mikesinsectkeyshymenoptera/

Keys to Coleoptera - go to https://sites.google.com/site/mikesinsectkeys


The diptera apart from a few exceptions have two wings and a pair of drumstick-like appendages behind them, called halteres

They are divided into two main groups:

A  Antennae with at least five segments, usually long and thin AND with the anal veins of the wing diverging from one another (or there are very few veins on the wing).


B  Antennae usually with less than five segments. If with more than five, then the antennae are usually not long and thin AND the veins towards the back of the wing converge and meet to form an enclosed area (the anal cell) or they converge and join the wing margin close together.


Subpages (2): Brachycera Nematocera