Even in mild winters life for a small insect in Britain is extremely difficult. For this reason most insects survive the winter as eggs, caterpillars or chrysalises which lie dormant in tree holes, amongst leaf litter or even underground. There are a few, though, that over-winter as adults, hibernating through the worst of the weather and waking when temperatures rise.
One species of insect which chooses to hibernate in adult form is the green lacewing.
In the UK we have about forty species of lacewing but only one of them hibernates, the common green lacewing (Chrysoperla carnea). The body of this creature is a little prehistoric in appearance, it has large eyes and long antennae which make it look rather unattractive. However it does have the most wonderful set of wings imaginable. These large wings are translucent and intricately veined, reflecting light at slightly different angles just as you might expect to see from leaded windows.
To gardeners the green lacewing is a good-guy because it is a potent predator of aphids and so should be welcomed into our gardens. The more lacewings we can support through the winter in our gardens, the bigger head start they will have when it comes to tackling aphids in the spring and summer. To help them, we need to think about where they like to hibernate.
Generally lacewings hibernate amongst leaf litter so if you tidy leaf litter away from paths consider leaving it in a corner of the garden until the spring, maybe use it as a mulch but don't pack it tightly into a compost bin from which the insects will never be able to emerge.
Evergreen plants such as ivy are also useful places for many hibernating insects. Lacewings, as well as ladybirds, will readily hibernate in outbuildings, I once found many lacewings in the crevice between two sheets of plywood which I had left against a wall. One of the reasons why they had taken to this location is that they always crawl upwards, so they had landed nearby and crawled upwards into the tight space near the top of the plywood.
It is possible to buy, or make, insect hibernating 'houses' and some of these are specially made for lacewings but, in my opinion, such structures are no substitute for wildlife-friendly gardening. If you do have a lacewing house, it is important to remember to clean it out in early autumn, earwigs often take up residence in summer and will kill any lacewings as they arrive.