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Butterfly taxonomy (classification) The skippers The swallowtails The whites The hairstreaks, coppers and blues. Includes the Duke of Burgundy. The nymphalids, fritillaries and browns. Includes the Monarch.

Similar Species

This page describes various differences between similar species. This list is ordered by the vernacular name of the first species.

Adonis Blue and Brown Argus

Description not yet available.

Adonis Blue and Chalkhill Blue

The female Adonis Blue is easily mistaken for a female Chalkhill Blue and the two species occasionally fly together toward the second half of August on some sites. Distinguishing the two is not at all easy. One guideline is that the pale scales on the hindwings, between the red dots and the white fringe, are blue in a female Adonis Blue, and white in a female Chalkhill Blue.


Adonis Blue female (left) and Chalkhill Blue female (right)

Adonis Blue and Common Blue

The male Adonis Blue is often mistaken for a male Common Blue. However, the two can be distinguished by looking at the white fringes of the wings. Only on the Adonis Blue are the fringes intersected by black bands. This diagnostic can also be used to distinguish the two species based on their undersides.


Adonis Blue male (left) and Common Blue male (right)

Adonis Blue and Northern Brown Argus

Description not yet available.

American Painted Lady and Painted Lady

Description not yet available.

Bath White and Orange-tip

Description not yet available.

Berger's Clouded Yellow and Clouded Yellow

Of the three species of Clouded Yellow found in the British Isles, the Clouded Yellow is both the commonest and the easiest to identify. When in flight, the orange appearance of the Clouded Yellow is unlike any other British butterfly. When settled, the lemon-coloured underside of the Clouded Yellow allows us to distinguish this species from Berger's Clouded Yellow which has a much paler underside. This diagnostic holds true even in the helice form of female Clouded Yellow where the orange colouring is replaced by a creamy white.


1. Clouded Yellow 2. Clouded Yellow (f. helice)
3. Berger's Clouded Yellow (male) 4. Berger's Clouded Yellow (female)

Berger's Clouded Yellow and Pale Clouded Yellow

Distinguishing Berger's Clouded Yellow and Pale Clouded Yellow is not at all easy and the identity of a given individual can only be reliably determined if it has been raised from the larval stage when the difference between these two species is obvious. However, there are some general rules of thumb that can be applied to the adults and a combination of these can give an indication of the species one way or the other. Unfortunately, all of these diagnostics are comparitive and, unless you are familiar with both species, can be difficult to judge with any certainly. The first diagnostic is with respect to wing shape, where the Pale Clouded Yellow has a more pointed apex to the forewing than that of Berger's Clouded Yellow. The other diagnostics are only applicable if the upperside is visible. Given that all of the clouded yellows settle with their wings closed, the only way to get a good view of the upperside is to catch the individual in order to examine it (which should not be attempted unless you are certain you won't harm the individual). The second diagnostic is that the orange spot found on the upperside of the hindwing is brighter in the Berger's Clouded Yellow than the Pale Clouded Yellow. The final diagnostic concerns the dusting of grey scales found on the forewing upperside next to the body. This patch of grey scales is a more-extensive in the Pale Clouded Yellow than Berger's Clouded Yellow.


1. Berger's Clouded Yellow (male) 2. Berger's Clouded Yellow (female)
3. Pale Clouded Yellow (male) 4. Pale Clouded Yellow (female)

Black Hairstreak and White-letter Hairstreak

Both Black Hairstreak and White-letter Hairstreak are very local species, but do fly together on rare occasions. There are two features that distinguish these species. The first is that the Black Hairstreak has a row of distinctive black dots running along the inside of the orange band on the underside of the hindwing, that is absent in the White-letter Hairstreak. The second is that the White-letter Hairstreak has a more pronounced white line on its hindwing, forming a letter "W" from which the White-letter Hairstreak gets its name. This line is less prominent in the Black Hairstreak.


Black Hairstreak (left) and White-letter Hairstreak (right)

Brown Argus and Chalkhill Blue

Description not yet available.

Brown Argus and Common Blue

Of the two sexes, it is the female Common Blue that causes most confusion with the Brown Argus. The blue present in a female Common Blue is highly variable, with individuals ranging from almost completely blue through to completely brown. It is this latter colouring that causes the most confusion. Even so, the Brown Argus has no blue scales, but may give off a blue sheen from the wings and the hairs found on the thorax and abdomen. Another diagnostic is that the Brown Argus normally has a prominent dark spot in the centre of the forewings.


Brown Argus (left) and female Common Blue (right)

Differentiating Brown Argus and Common Blue from their undersides is even more problematic, and we need to resort to the pattern of spots. Here we have two distinguishing features. The first is that the Common Blue has a spot on the underside of the forewing that is absent in the Brown Argus. The second is that two of the spots on the leading edge of the hindwing are relatively-close in the Brown Argus, almost forming a "figure of eight", but are more spaced apart in the Common Blue. This diagnostic is particularly useful if the underside of the forewing isn't visible.


Brown Argus (left) and Common Blue (right)

Brown Argus and Northern Brown Argus

Although very similar in appearance, the Brown Argus and Northern Brown Argus can be separated by location in the British Isles. However, this situation may change with global warming as the Brown Argus moves further north.


Brown Argus and Northern Brown Argus distributions

Chalkhill Blue and Common Blue

Description not yet available.

Chalkhill Blue and Northern Brown Argus

Description not yet available.

Clouded Yellow and Pale Clouded Yellow

Of the three species of Clouded Yellow found in the British Isles, the Clouded Yellow is both the commonest and the easiest to identify. When in flight, the orange appearance of the Clouded Yellow is unlike any other British butterfly. When settled, the lemon-coloured underside of the Clouded Yellow allows us to distinguish this species from Pale Clouded Yellow which has a much paler underside. This diagnostic holds true even in the helice form of female Clouded Yellow where the orange colouring is replaced by a creamy white.


1. Clouded Yellow 2. Clouded Yellow (f. helice)
3. Pale Clouded Yellow (male) 4. Pale Clouded Yellow (female)

Common Blue and Holly Blue

Description not yet available.

Common Blue and Northern Brown Argus

Of the two sexes, it is the female Common Blue that causes most confusion with the Northern Brown Argus. The blue present in a female Common Blue is highly variable, with individuals ranging from almost completely blue through to completely brown. It is this latter colouring that causes the most confusion. Even so, the Northern Brown Argus has no blue scales, but may give off a blue sheen from the wings and the hairs found on the thorax and abdomen. Another diagnostic is that the Northern Brown Argus normally has a prominent dark spot in the centre of the forewings and, in the case of the artaxercxes subspecies of Northern Brown Argus, it a distinctive white dot. Any identification challenges are usually, therefore, with respect to the salmacis subspecies of Northern Brown Argus that does not have this white spot.


Common Blue female (left) and Northern Brown Argus ssp. salmacis (right)

Differentiating Common Blue and Northern Brown Argus from their undersides is even more problematic, and we need to resort to the pattern of spots. Here we have two distinguishing features. The first is that the Common Blue has a spot on the underside of the forewing that is absent in the Northern Brown Argus. The second is that two of the spots on the leading edge of the hindwing are relatively-close in the Northern Brown Argus, almost forming a "figure of eight", but are more spaced apart in the Common Blue. This diagnostic is particularly useful if the underside of the forewing isn't visible.


Common Blue (left) and Northern Brown Argus (right)

Common Blue and Silver-studded Blue

Description not yet available.

Cryptic Wood White and Wood White

The Cryptic Wood White and Wood White can only be differentiated by a detailed examination of their genitalia.

Dark Green Fritillary and High Brown Fritillary

The Dark Green Fritillary and High Brown Fritillary are most easily distinguished by their undersides, since only the High Brown Fritillary has a row of "ocelli" just inside the outer margin. In addition, as the name suggests, the High Brown Fritillary has a predominately brown hue to the underside, whereas the Dark Green Fritillary is predominately green.


Dark Green Fritillary (left) and High Brown Fritillary (right)

It is much more difficult to distinguish the Dark Green Fritillary from the High Brown Fritillary based on their uppersides. However, the first row of dots from the outside edge of the forewing upperside do give a clue - the 3rd dot from the apex of the forewing is in line with the other dots in the Dark Green Fritillary, but indented toward the body in the High Brown Fritillary.


Dark Green Fritillary (left) and High Brown Fritillary (right)

Dark Green Fritillary and Queen of Spain Fritillary

Description not yet available.

Dark Green Fritillary and Silver-washed Fritillary

Description not yet available.

Essex Skipper and Large Skipper

Description not yet available.

Essex Skipper and Lulworth Skipper

Description not yet available.

Essex Skipper and Small Skipper

Essex Skipper and Small Skipper can be distinguished by the colour of the underside of the tips of the antennae. In the Essex Skipper, this area is black and in the Small Skipper it is brown. This holds true for both sexes.


Essex Skipper (left) and Small Skipper (right)

Males can also be distinguished by the sex brand found on the upperside of their forewings. The sex brand of a male Essex Skipper is relatively-short when compared with that of the male Small Skipper. The sex brand of a male Essex Skipper also runs parallel with the leading edge of the forewing, but at an angle in the male Small Skipper.


Male Essex Skipper (left) and Male Small Skipper (right)

Gatekeeper and Meadow Brown

Description not yet available.

Glanville Fritillary and Heath Fritillary

The Glanville Fritillary and Heath Fritillary are easily distinguished in the British Isles since the Glanville Fritillary is generally only found on the Isle of Wight, with a small colony on the mainland, where Heath Fritillary do not occur. Where these two species do occur together on the continent, they are most easily distinguished from their undersides. The Glanville Fritillary has several spots on the underside that are not present in the Heath Fritillary.


Glanville Fritillary (left) and Heath Fritillary (right)

The spotting is also a distinguishing feature when looking at the upperside, where the Glanville Fritillary has spots on the upperside of the hindwing that are absent in the Heath Fritillary.


Glanville Fritillary (left) and Heath Fritillary (right)

Green-veined White and Large White

Description not yet available.

Green-veined White and Orange-tip

Description not yet available.

Green-veined White and Small White

The Green-veined White and Small White are most easily distinguished by their undersides, where the Green-veined White has pronounced markings along the veins which are absent in the Small White.


Green-veined White (left) and Small White (right)

It is much more difficult to distinguish between the Green-veined White and Small White based on the upperside, since the amount of marking is highly variable. In general, the veins of the Green-veined White are more pronounced. Also, the marking at the apex of the forewing of a Green-veined White often extends down the along the edge of the forewing and is not contiguous. The marking at the apex of a Small White never extends down the edge of the forewing and is unbroken.


Green-veined White male (left) and Small White male (right)

High Brown Fritillary and Queen of Spain Fritillary

Description not yet available.

High Brown Fritillary and Silver-washed Fritillary

Description not yet available.

Holly Blue and Small Blue

Description not yet available.

Large Heath and Small Heath

Description not yet available.

Large Skipper and Silver-spotted Skipper

Description not yet available.

Large Skipper and Small Skipper

Description not yet available.

Large Tortoiseshell and Small Tortoiseshell

Description not yet available.

Large White and Small White

In general, the Large White and Small White can be distinguished based on size. However, there are occasions when a "small" Large White flying with a "large" Small White causes confusion. In terms of uppersides, a distinguishing feature is the black marking at the apex of the forewing. This is generally more vertical than horizontal in the Large White, and more horizontal than vertical in the Small White.


Large White (left) and Small White (right)

Distinguishing these two species based on their underside is a little more difficult. Aside from size, there is sometimes a hint of the upperside markings where, again, those at the apex of the forewing can give an indication of the species.


Large White (left) and Small White (right)

Lulworth Skipper and Small Skipper

Description not yet available.

Mountain Ringlet and Scotch Argus

Description not yet available.

Pearl-bordered Fritillary and Small Pearl-bordered Fritillary

The Pearl-bordered Fritillary and Small Pearl-bordered Fritillary are most easily distinguished by their undersides. Both species have a row of 7 white "pearls" running along the edge of the hindwing (hence their vernacular names). However, the remainder of the underside of the hindwing is quite different. The Pearl-bordered Fritillary exhibits 2 very distinct additional "pearls", whereas the Small Pearl-bordered Fritillary has a mozaic of white, oranges and browns and, as such, has the more colourful underside.


Pearl-bordered Fritillary (left) and Small Pearl-bordered Fritillary (right)

It is much more difficult to distinguish Pearl-bordered Fritillary and Small Pearl-bordered Fritillary based on their uppersides. However, there are two general differences. The first is with regard to the row of chevrons at the edge of the forewings. In the Pearl-bordered Fritillary, these chevrons are often "floating" and not attached to the outer margin, whereas these chevrons are attached to the edge of the forewing in the Small Pearl-bordered Fritillary. The second is with regard to the row of spots found next to these chevrons. In the Pearl-bordered Fritillary, each of these spots is positioned midway between neighbouring markings. In the Small Pearl-bordered Fritillary, the dots are not midway, but distinctly closer to the chevrons.


Pearl-bordered Fritillary (left) and Small Pearl-bordered Fritillary (right)

Silver-washed Fritillary and Queen of Spain Fritillary

Description not yet available.
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