{"id":15286,"date":"2022-01-16T11:55:44","date_gmt":"2022-01-16T19:55:44","guid":{"rendered":"http:\/\/www.vicnhs.bc.ca\/?p=15286"},"modified":"2022-01-26T10:45:30","modified_gmt":"2022-01-26T18:45:30","slug":"2022-january-16","status":"publish","type":"post","link":"https:\/\/www.vicnhs.bc.ca\/?p=15286","title":{"rendered":"2022 January 16"},"content":{"rendered":"
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2022 January 16<\/strong><\/p>\n

\u00a0<\/strong> \u00a0\u00a0 Jeremy Tatum writes:\u00a0\u00a0 I occasionally get a telephone call from someone who says s\/he has an interesting moth at home, and could I identify it, please.\u00a0 On asking for a description, I may be told that it is brownish and greyish with spots and streaks.\u00a0 Needless to say,\u00a0 I can\u2019t identify it from that!\u00a0 It is indeed difficult to describe the colours and pattern of a butterfly or moth wing.\u00a0 It helps if you are familiar with the \u201cgeography\u201d of a wing, and I hope these notes will help a bit with that.<\/p>\n

A moth has two pairs of wings \u2013 the forewings <\/strong>and the hindwings<\/strong>.\u00a0\u00a0 And each wing has an upperside<\/strong> and an underside.\u00a0 <\/strong>The hindwings are also sometimes called the \u201cunderwings\u201d \u2013 and this name occurs in the English name of some moths, such as the familiar Large Yellow Underwing.\u00a0 I prefer not to use the word \u201cunderwing\u201d, because of possible (frequent!) confusion with \u201cunderside\u201d.<\/p>\n

A moth wing is roughly triangular<\/strong> in shape, and like any good triangle it has three sides and three angles, and it is helpful to know and to use the names of these sides and angles.<\/p>\n

First, the sides.<\/strong><\/p>\n

\u00a0<\/strong>\u00a0 <\/strong>There is the leading edge <\/strong>or costa.<\/strong><\/p>\n

\u00a0 <\/strong>Then the side farthest from the head is the outer margin<\/strong> or termen <\/strong>(adjective \u201cterminal\u201d)<\/p>\n

And the side nearest the body is the inner margin<\/strong>.<\/p>\n

The word \u201ccosta\u201d is used quite a lot;\u00a0 the word \u201ctermen\u201d not quite so much.<\/p>\n

 <\/p>\n

Now for the angles.<\/strong><\/p>\n

\u00a0<\/strong>The angle nearest the head of the moth is the base<\/strong>, or the basal angle<\/strong>.<\/p>\n

The tip of the wing is the apex.\u00a0 <\/strong>(Adjective \u201capical\u201d)<\/p>\n

The third angle is the inner angle <\/strong>or tornus<\/strong>.<\/p>\n

 <\/p>\n

Thus the outer margin<\/strong> is opposite the base.<\/strong><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/strong>The inner margin<\/strong> is opposite the apex.<\/strong><\/p>\n

\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 <\/strong>The costa<\/strong> is opposite the inner angle.<\/strong><\/p>\n

 <\/p>\n

The wing of a moth has a number of veins<\/strong>.\u00a0 (They are not veins in quite the same sense as the veins of mammals, but that is the word that is generally used.)\u00a0 There are various schemes for numbering and naming these veins.\u00a0 The venation scheme varies from Family to Family (not to mention from author to author!) but in a general way they usually start with 1 being the vein nearest the inner margin, and the number increasing as you move along the outer margin from tornus to apex.<\/p>\n

 <\/p>\n


\nOperophtera occidentalis\u00a0 <\/em>Val George<\/p>\n

 <\/p>\n

The spaces between the veins are cells.\u00a0 <\/strong>You will see that most of the cells are \u201copen\u201d, because the veins come to an end at the outer margin.\u00a0 However, you will notice a large closed<\/em> cell, starting narrowly near the base, widening and extending roughly parallel to the costa about 2\/3 the length of the costa.\u00a0 This large cell is called the disc.<\/strong><\/p>\n

\u00a0<\/strong>\u00a0 You\u2019ll notice a small dark spot inside the disc.\u00a0 The presence or absence of a discal spot<\/strong> is sometimes helpful in identifying a moth.\u00a0\u00a0 If I call the first easily-visible vein near the inner margin \u201c1\u201d, you will notice that the cell between veins 4 and 5 is darker than the two adjacent cells.\u00a0 That is one way in which I tell the difference between Operophtera occidentalis <\/em>and O. brumata<\/em>.\u00a0 The point here, however, is that you can already see how knowing the \u201cgeography\u201d of a wing and the words to use helps in describing it.<\/p>\n

\u00a0 <\/strong>Many moths, particularly geometrids, may have one or more transverse lines <\/strong>or cross lines <\/strong>crossing\u00a0 the wing roughly parallel to the outer margin.\u00a0 You can help to describe a moth by describing the colour, shape and width of these transverse lines, and where<\/em> they are on the wing.\u00a0 If a line is close to the base of the wing, you can call it a basal<\/strong> cross line.\u00a0 If it goes smack across the middle of the wing, you can call it a medial <\/strong>cross line.\u00a0 If it is a little before the middle, it is an antemedial (am) <\/strong>line.\u00a0 If it is a little beyond the middle, it is a postmedial (pm) <\/strong>line.\u00a0 If it is just a little before you get to the outer margin (termen) it is a subterminal <\/strong>line.<\/p>\n

 <\/p>\n

<\/em><\/p>\n

Scopula quinquelinearia\u00a0 <\/em>Jochen M\u00f6hr<\/p>\n

 <\/p>\n

In describing the moth above, I would say that there is a faint antemedial line (or, for short, a faint am line;\u00a0 some might describe it as a basal\u00a0 line), a prominent medial line, a pm line, and two close, faint, ill-defined subterminal lines.\u00a0 The outer margin is also delineated with a thin, dark line.\u00a0 Beyond the margin you will see a fringe of delicate hair-like scales.\u00a0 This fringe is called, unsurprisingly, the fringe<\/strong>.\u00a0 As for the shapes of these lines, you can say \u201cwiggly\u201d \u2013 though with a bit of imagination you may be able to do a little better than that.<\/p>\n

A moth wing typically has a whole bunch of streaks and spots.\u00a0 Many moths, noctuids in particular, have a collection of three prominent spots (\u201cstigmata\u201d\u00a0 – singular \u201cstigma”), easily recognizable by their characteristic shapes.\u00a0 \u00a0There is a reniform stigma <\/strong>or spot <\/strong>(kidney-shaped), an orbicular stigma <\/strong>(more or less round), and a claviform stigma <\/strong>(supposed to be club-shaped, but in any case elongated).\u00a0 Not all are always present or obvious.\u00a0 A description of these three spots is often helpful.<\/p>\n

 <\/p>\n

<\/em><\/p>\n

Parabagrotis sulinaris <\/em>Jeremy Tatum<\/p>\n

The moth above has very obvious reniform and claviform spots.\u00a0 The orbicular spot may be that bump attached to the pale costal streak. These spots are in a dark central area bounded by the pale costal streak, a pale am line and a darker pm line.\u00a0 The pm line is proximally dark but pale distally.\u00a0 (See how the use of technical words actually helps in making a clear description.)<\/p>\n

I\u2019ll leave this moth with you, so you can practise describing it as best you can \u2013 in a way that is an improvement over \u00a0\u201cbrownish and greyish with spots and streaks\u201d.\u00a0 For example, have a go at describing the space between the postmedial and\u00a0 subterminal lines. \u00a0And describe the terminal area.\u00a0 See the row of dark V-shaped marks at the termen.\u00a0 Und so weiter<\/em>.\u00a0\u00a0 Good luck.<\/p>\n

\u00a0<\/strong><\/p>\n

 <\/p>\n

\u00a0<\/strong><\/p>\n

 <\/p>\n

 <\/p>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

2022 January 16 \u00a0 \u00a0\u00a0 Jeremy Tatum writes:\u00a0\u00a0 I occasionally get a telephone call from someone who says s\/he has an interesting moth at home, and could I identify it, please.\u00a0 On asking for a description, I may be told that it is brownish and greyish with spots and streaks.\u00a0 Needless to say,\u00a0 I can\u2019t […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[],"class_list":["post-15286","post","type-post","status-publish","format-standard","hentry","category-invertebrate-alert"],"_links":{"self":[{"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=\/wp\/v2\/posts\/15286","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=15286"}],"version-history":[{"count":3,"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=\/wp\/v2\/posts\/15286\/revisions"}],"predecessor-version":[{"id":15309,"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=\/wp\/v2\/posts\/15286\/revisions\/15309"}],"wp:attachment":[{"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=15286"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=15286"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.vicnhs.bc.ca\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=15286"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}