Welsh Journals

FLIES ON THE WINDOW PANE MRS. M. J. MORGAN "Nasty buzzing bluebottle open the window and let it out!" Set free, the fly disappears rapidly towards the sunshine, and the housewife complains of the spots left behind on the glass. But the flies and other insects often repay a second look and may be of considerable interest to the naturalist. Window panes have been well known for many years as a good hunting ground for entomologists. We will not spend long on the Bluebottle or Blowfly, seeker out of fresh meat on which to lay its eggs; its allies the greenbottles, notorious for causing sheepstrike and the Common Housefly Musca domestica, which breeds in waste of all kinds before coming indoors to inspect our tea tables for delicacies. Let us have a look at some of the other flies crawling on the glass or desperately trying to batter their way through. The Stable Fly, Stomoxys calcitrans (L.) is sometimes a pest in the country when it comes indoors and crawls on the windows. At first glance it appears to be an ordinary Housefly, but closer inspection reveals a sharp proboscis under the head instead of the usual lapping mouthparts. A "biting housefly" is almost sure to be really a Stable Fly, and even more difficult to catch and despatch. The daddy-long-legs or crane flies Tipulidae are well known insects, easily recognised as they dance up and down trying to escape outside. It may not be as well known that the larvae of the large species are the leather jackets which can do considerable damage to the roots of plants, at times killing off considerable patches of lawn turf as a result of their feeding activities. Surprisingly, there are nearly 300 species in Britain, only a few of them large, many of them delicate flies only a few millimetres in length. Besides those which eat roots, other larvae feed in rotten wood, moss, wet mud and even ponds and streams. So tiny and fragile that they are easily overlooked are members of various families of gnats and midges. Most of them are harmless to man, like the land midges Mycetophiloidea which breed in compost heaps, decaying vegetation and fungi, or the gall midges Cecidomyiidae whose larvae live in the tissues of growing plants. Several families of midges start life as aquatic larvae. The adults can be seen swarming in dancing clouds on still summer evenings. A few may find their way indoors and come to rest on the window where the large plumed antennae of the male are clearly visible, held out in front of the head. The non-biting Chironomidae outnumber the related family of biting midges Ceratopogonidae though the latter are much better known; for- tunately they rarely seem to come indoors, where one may have to retreat to escape them on sultry summer evenings.