Aeshnidae family - the Hawkers. These are the hawkers, and they are the largest and swiftest European dragonflies. The adult body length ranges from 50 - 120 mm, and the wingspan is up to 150 mm. Above is the nymph of Aeshna grandis, the brown hawker. The adult flies from July - October in England and Ireland. It is fairly easily recognised as it has amber-tinted wings and a brown body. The adult wingspan is around 102 mm, and body length 73 mm. Adults tend to hawk around pond edges and down the middle of streams. The males are fiercely territorial and will attack other males. The females deposit their eggs in plants or floating wood.

miniature whirlwinds that move the air much faster over the upper wing surface, and so reduces air pressure and increase lift. Damsel flies usually have slimmer abdomens in both adults and nymphs. Both sub-orders usually fly during the day. During the Carboniferous there were huge dragonflies (with wingspans as large as that of a seagull today) to be found in what is now England. At that time insects were the only flying animals. It is believed that the huge dragonflies were slower fliers that those of today.

The nymphs (see Aeshna grandis left) are aquatic, carnivorous and sluggish. On hatching from the eggs the larvae start feeding at once. They have a prehensile lower lip (called the mask) which is folded under the head at rest (see the photograph on the left). This has moveable teeth, and the whole thing can shoot out at great speed to grab prey. On the left the mask is partially extended. Dragonfly nymphs can swim very fast for a short distance by jet propulsion. They can forcibly eject water from the gill cavity in their abdomen and this provides forward thrust for a short distance - usually enough to grab prey. The larvae breathe underwater through tracheal gills. They tend to creep around the bottom of ponds and streams searching for prey. When a nymph is about to moult into an adult it crawls out of the water. Dawn or dusk during fine weather are the most common times for moulting. There are usually 10 - 15 moults as nymphs. It can take nymphs from 1 to 5 years to mature depending on species.

The adults are strong fliers and eat other insects, especially mosquitoes, black flies and other small flies, that they catch on the wing. They have a row of stiff bristles on either side of their legs, so the three pairs form a basket to scoop flying prey. However because of the positioning of the front legs Odonata cannot walk or crawl. Dragonfly flight speed has been recorded as 7.0 metres per second with a wing beat of 38 per second. Compare this with other insects.

Females and males of the same species are often different colours, and younger adults are usually a paler colour than older ones. The beautiful colours of the adults fade after death.

The venation of the wings is used in identification to species level, however there is disagreement between entomologists in naming the veins, so identification for a beginner is usually easiest using illustrations.

They have 10 or 11 abdominal segments. All males have a pair of claspers on segment 10, and their reproductive organs on segment 2 or 3. In females the ovipositor is in segment 8 or 9. Some females may have a pair of appendages on segment 10.

Before mating the male must transfer sperm from the genital opening on segment 9 to the reproductive organs on segments and 3. Then on finding a female he grabs her by the neck with his claspers. She curves her body around until the tip of her abdomen touches his reproductive organs in segment 2 and 3 to collect the sperm. This is known as the copulation wheel. After mating the pair may fly in tandem with the male leading. Females mate with more than one male and store the sperm from the matings, although she tends to use the sperm from the last mating. The male mating organ contains a structure that allows him to scrape or push aside the sperm from previous matings before deposting his own in the most favourable spot. The elngth of time he holds on to the female (the copulation wheel) will also prevent her mating with another.

Libellulidae family, commonly known as the Darters and Skimmers, has 1300 species worldwide, and 14 native British species. Libellulids are shorter than most other Ansioptera, and a flattening of the abdomen makes them appear stout. In Europe the body length ranges from 18 - 75 mm. Unlike other Ansioptera they do not patrol a territory, but tend to perch in the same spot and dart out to capture any passing prey. In the UK the adults fly from May until September.

On the left is the nymph of Libellula quadrimaculata, the Four-spotted chaser.

Libellula depressa, right in the Libelludidae family, is also known as the broad-bodied chaser and broad-bodied Libelulla.

The males have a blue abdomen except for brown spots at the side. The females have yellow spots down the side of a brown abdomen. Both have dark brown patches at the base of the wings. The wingspan is around 74 mm and body length around 44 mm. The males are territorial and use the same parch for days on end. Females tend to rest on vegetation near to ponds. They are fairly common in southern England and Wales. Adults fly from late May - September.

They fly from dawn to dusk, and prefer habitats that are open. The nymphs are 40 - 46 mm long when fully grown. They are tolerant of semi-polluted waters, so can breed in canals, and are also found in large ponds and the weedy margins of lakes.

The adult female lays her eggs in floating timber or vegetation close to the water's edge.