In Holland there are sixty species. (Different from colour, size and spots)  Worldwide 5000 species. The Seven-spot ladybird and the  two-spotted ladybird are in Holland the most common ladybirds. 
In danger they are able to reflex-bleed. From the leg joints they release an orange yellow oily toxin with a strong repellent smell. (hemolymph or insect bleed)  It is a little predator. Both the larva and the ladybird itself feed on aphids and insects larvae. There are also species, which feed on mildew and even scale insects. In wintertime ladybirds hibernate, often in large groups  in sheltered places.
The eggs are laid on or under the leaves.The larval period lasts about three weeks.

German: Marienkäfer   French: Coccinellidés, coccinelles, bêtes à bon Dieu

Orange Ladybird (Halyzia sedecimguttata) They feed on mildew. (refers to certain kinds of mold or fungus) It has 16 creamy-white coloured spots, but there can be as few as 14 spots. The head and legs are also orange. The eyes are black. Its elytra and pronotum (the hardened plate that protects its thorax and head) are almost transparent around the rim of the ladybird. 6-9 mm. Frequently found around maples and ashes  
German: Sechzehnfleckiger Pilz-Marienkäfer   French: Grande Coccinelle orange    

Asian Ladybird, Asian lady beetle, Multicolored Asian lady beetle, Harlequin lady beetle (harmonia axyridis). This insect is native to northeastern Asia and has been introduced In Europe and America to control agricultural pests. But now it is spreading rapidly throughout the United States and Europe.
Asian lady beetle has a black mark on the pronotum that looks like an  "M". ( not always visible) There’s a wide variation in background colour and number of spots. The elytra usually display a wide transverse "keel" at the apex. Further they have all kinds of colours and several numbers dot. They have pale brown legs Just like the other ladybirds they hibernate in clusters  Length 5 - 8 mm

The first Asian ladybird on the photo to the right has only six dots. The black mark on the pronotum don't looks like an  "M". The patron is similar to Ten-Spot Ladybird Beetle (Adalia decempunctata) Like the Asian ladybird it has a wide transverse "keel" at the apex. The Ten-Spot Ladybird Beetle is smaller (3,5 - 5 mm)
The second Asian ladybird has no dots. Maybe because it is very young. The dots appear later than.

German: Asiatische Marienkäfer  French: Coccinelle asiatique multicolore   

It was a good spot, for there were many aphids on the bamboo leaves.   

When they are young, they have a beautiful green colouring. It changes in  grayish green when they are old. 
You can find this species in birches. In my garden I find them in the bay shrubs near the birch. 
They feed on leaves of trees and bushes such as birch, apple, strawberry. They are no pest in my garden.
The larvae feed on roots.
Europe. In America (Green immigrant leaf weevil) since 1906 (first found in New York)

April - July  

This snout beetle I’ve often seen in June 2008 in the evening in the Goldenrod. When you try to catch it, it prefers to fall down. 
Length: 4 - 6 mm
Sandy soils. Oft along the coast in the dunes.
Western and Central Europe.  April, Mai, June
There are similar snout beetles like species of the family Strophosoma.

Photos below: April 2009

German: Graue Kugelrüßler     

The Soldier beetles on the flower: Common red soldier beetle (Rhagonycha fulva)
In the Netherlands are 50 species of the soldier beetle. Another name is leatherwing. They are soft-bodied, straight sided beetles. The common red soldier beetle has an orange colour and is only darker at the end. Named soldier because the colour of these beetles is similar to a 19^th century army uniform.
They hunt  for small insects, eat nectar and pollen on the top of flowers and they spend much of their time mating.
In July I  find them (rhagonycha fulva) everywhere in the garden. Especially on the flowers of the parsley and celery.
This beetle is very common in Europe. On holidays in England I saw them also in large numbers at Stonehenge and in Cornwall.

German: Weichkäfer  

Rhagonycha fulva

Raspberry beetle  (Byturus tomentosus) 

Two small beetles on the flower of the greater celandine. They feed on pollen and nectar. It lays eggs on the flowers of raspberry, blackberry and loganberry plants. which hatch into pale brown larvae. The pale brown larvae lives in the fruit. 
I always examine the raspberries before I start to eat.
In late summer, the larvae move into the soil where they hibernate as pupae. The beetle lives three months.
Of course this beetle is a pest. It is a common species in north-central Europe.
Measuring 4 mm
There is not much difference with the Byturus  aestivus. B. tomentosus has smaller eyes.
The photos below are taken in Arpil 2009.
   

German: Himbeerkäfer   French: Ver des framboises

19 May a number of this species flew in the garden. It was difficult to take photos because they were continuously in movement. It is a smaller relative of the Cockchafer or May Bug. It appears on sandy soils. Garden chafers have chestnut brown wing casings which are covered in tiny hairs. They have fan-like antennae, like all chafers. The wing cases are chestnut brown and are covered in tiny hairs.  
After the females have deposited 70% of the eggs, they start a short feeding period on trees and shrubs and cause damage to fruit trees. The rest of the eggs are laid on another place.
Eggs have a developing time of four weeks. The larvae feed on the roods of the grass and can cause much damage. They pupate in October and hibernate as a pupa in the soil.
Size: Approximately 10mm long.   Flying time: May-July  

German: Gartenlaubkäfer  French: Hanneton des jardins, Hanneton horticole

Click beetles ( Elateridae) Also called elaters, skipjacks, snapping beetles, or spring beetles)
 
In the Netherlands there are about 70 species. They can flip themselves 30 cm in the air, when they are in danger. Sometimes they land on their back. But that’s not a problem. They will flip again. A pointed projection suddenly snaps, when the beetle arches its body. This causes a clicking noise. Which species they are, is difficult to say. The first is possibly Hemicrepidius niger, the other possibly Athous haemorrhoidalis. But it is not certain.
The beetle eats vegetable food like nectar, pollen, thumbs and flowers
The larvae are called wireworms. They feed on the roots of plants, and they often cause much damage  
German: Schnellkäfer  French: élateridés
Photo's 2009
Click beetle Athous haemorrhoidalis. First 12 mm  Second 15 mm.
  Click beetle Hemicrepidius cf niger   cf: probably

Lagria hirta or Lagria atripes. Two very similar species.
Familie: Tenebrionidae

It is a darkling beetle. Family: Tenebrionidae
They have a soft body and are rather sluggish. But they can fly. The brown wing cases are very hairy. The head and torax is black.
They eat among other things nectar and pollen.
The larva feed on decaying matter in leaf-litter and turf

Flying time: May – August   Length: 7-10mm

Longhorn beetles or long-horned beetles (Cerambycidae) There are more than 20000 species on the world. In the Netherlands it’s a lot less.
Several larvae are boring into wood. Several species can cause extensive damage to either living trees or to wood in buildings (the old house borer Hylotrupes bajulus ).
The Longhorn beetles feed on flowers, pollen and leaves.

Corymbia rubra Leptura rubra and Stictoleptura rubra are former scientific names. They are still used. 

Native in Europe, North Africa, and Asia. The males have yellowish-brown wing covers. The torax is black. The females (last 3 photographs) have  red wing covers. The torax is red too and it is larger. Just like most of the longhorn beetles it has long antennae,
The larvae of this beetle live for several years  in dead wood of pine and fir trees,
Length :10-20 mm  
female            German: Rothalsbock, Gemeiner Bockkäfer  French: Lepture rouge

German: Gemeiner, Echter Widderbock  French: Clyte bélier

In May, June, you can find them on flowers. This was on a leaf and it did not like the camera. 
Two weeks later they were everywhere in the garden.
It is matt black in color. Legs and antennae are black with orange.
It's a small longhorn beetle. Length 4.5 to 7 mm

The larvae lives under the bark of decaying branches of different deciduous trees.

A common species in  Europe and Western Asia.

German: Mattschwarze Blütenbock  

Dasytes cyaneus

It looks like a small longhorn beetle and has a dark blue metallic sheen. Legs and antennae are black. They have very fine and short hair. 
The antennae of the females are shorter than the antennae of the males
Here you see the Dasytes on a Trout Lily (Erythronium dens-canis). The photo was taken in April. 

Size 5 mm.

The larvae are white, six-legged and hairy. They live in rotten wood and are predatory. The beetle emerges in spring. 
May to August.
Europe (except north), North Africa.

German: Blaue Wollhaarkäfer

Europe, North Africa, Asia

German: Grünliche Scheinbockkäfer 

German: Blaugrüner Scheinbock 

German: Eilkäfer  

This family is related to the ground beetles. Besides they can swim, they can fly too. The body has a streamlined shape. They store air under the elytra (the space between the abdomen and the elytra) They have no gills.
The larvae are also carnivores and aquatic. The beetles usually overwinter.
Sometimes I see a water beetle in the pond. But this was the first I found in the landing net, when I removed the leaves out of the pond.  Photos beetle 13/3/2010 Length: 10 mm.

It is mot easy to determine the dark water beetles from a photo. It may be one the family Agabus or of the family  Ilybius. The beetle looks like a Agabus bipustulatus.
If you are looking for a water beetle, you can find many at this page  (a German site)

German: Schwammkugelkäfer.

Stenus spec.

On the bottom picture you see a bug (Nabis) and another short rove beetle. This is a Stenus spec.  There are 80 species in the Netherlands. I found them together in a shell of a horse chestnut. Beginning in March 2009.

German: Kurzflügler  French: Staphylinidés

A dark Rove beetle. Only the legs and a part of the antennas are red.
This rove beetle is much larger than the rove beetles above. Length 12 to 15 mm.

Approximately one cm long. I found it under the leaves on the ground. Photo 11/4/2009. Furthermore, the beetle is not to identify.

Most of the family jewel beetles have a beautiful metallic colour. There are more than 15,000 species in the world. The shape is very recognizable. (oblong, narrower rear end) Most jewel beetles live in the tropics.
This is an Agrilus spec. Approximately one cm long. There are more identical species.
The larvae look a bit like a tadpole and they live under the bark. They can cause much damage.

    

German: Prachtkäfer  French: Agriles

The colour patron is variable. The beetles feed on pollen and nectar.
Size: 3 mm  On this photo the beetle was hidden on a flower of  feverfew.
They look like the museum beetle (Anthrenus museorum) and the Anthrenus pellio.

The larvae  feed on a variety of animal products such as woolens, carpets, hides, feathers, horns, bone and insect pupae. 
They can be pests in houses and museums and in insect collections.
In house they can damage clothes, furniture, carpets etc
In nature they are found in nests of birds and on dead animals. 
In 2009 I saw much more carpet beetles on the feverfew. Maybe other species of the family. 

German: Wollkrautblütenkäfer