Sylvicola fenestralis is a medium sized gnat of 6 to 10 mm length and has well marked wings, dark wing tips, with 3 dark stripes on the top of the thorax. It is very similar to other members of the genus and detailed examination is necessary.

It is very similar to S. cinctus, and can only reliably be separated by genital examination. However S. cinctus is smaller and has a maximum wing length of 6mm.

Your specimen should have these features:

• wing length 5-7.5mm
• wing cell m1 has a short flat base where it meets the discal cell (ie. not pointed)
• the hind femora is yellow but with a black tip and a faint dark median ring
• thorax always with three dark stripes

Note: females of S. cinctus will also have these features but with a maximum wing length of 6mm. If your specimen has a wing length of 6.5mm or longer it should be fenestralis.

Unless identified by a recognised expert, a photo is required, and the specimen should be examined with a microscope. In the comments box, state the key or ID method used and describe the size and identifying characters.

Often found near to buildings and also indoors at times. It is also found around sewage beds.

All year round.

Larvae are found in decaying matter.

Believed to be fairly common and widespread in Britain but difficulty of identification makes it hard to establish the true status.

Thought to be fairly frequent in Leicestershire and Rutland.