{"id":775,"date":"2012-03-19T20:33:53","date_gmt":"2012-03-19T20:33:53","guid":{"rendered":"http:\/\/tachinidae.org.uk\/blog\/?page_id=775"},"modified":"2012-04-23T12:54:49","modified_gmt":"2012-04-23T12:54:49","slug":"keys-projecting-mouth-edge","status":"publish","type":"page","link":"http:\/\/tachinidae.org.uk\/blog\/tutorials\/keys-projecting-mouth-edge\/","title":{"rendered":"Keys: Projecting mouth edge?"},"content":{"rendered":"

One of the most awkward questions that you are asked is to judge whether (when viewed laterally) the mouth edge is projecting beyond the base of the vibrissae or not. If you hold the specimen badly then you can make just about anything look projecting but sometimes even if you do everything correctly you can be left feeling unconvinced.<\/p>\n

First of all remember that in most of the places where it is asked in the keys the word \u201cobviously\u201d is used, which should be a clue because if you aren\u2019t sure then your fly probably isn\u2019t one with a projecting mouth edge. But for those times when it\u2019s a bit 50\/50 just read on and we\u2019ll go through all of the options.<\/p>\n

Species with a very obviously projecting mouth edge \u2013 Linnaemya<\/em>, the Eurithia<\/em> group, Eriothrix<\/em> and Aphria<\/em>. These all have a huge \u201ctop lip\u201d or \u201cover bite\u201d and they shouldn\u2019t be a problem at all. Here is an example of a Linnaemya vulpina <\/em>(with a protruding mouth edge) and a Sturmia <\/em>(without):<\/p>\n

\"\"<\/a>\"\"<\/a><\/p>\n

Then there are the oddities, such as Cadurciella tritaeniata<\/em>, which is supposed to have a protruding mouth edge but \u2026 well, you judge for yourself:<\/p>\n

\"\"<\/a><\/p>\n

Not very convincing is it? The key is to hold your specimen correctly to start with so that you are looking at it square on, laterally \u2013 imagine in your mind\u2019s eye orienting it so that the base of the back vibrissae is behind the base of the front vibrissae. If that doesn\u2019t work then try an old trick that I picked up a few years ago \u2013 turn your specimen so that you are looking at it from under the head \u2013 looking up \u2013 and you will see both vibrissae clearly and see the curve of the mouth edge. Now does it look like it projects beyond the base of the vibrissae?<\/p>\n

\"\"<\/a>
Cadurciella tritaeniata mouth seen from below showing that the mouth edge DOES project beyond the bases of the vibrissae.<\/figcaption><\/figure>\n
\"\"<\/a>
Exorista rustica mouth seen from below, showing that the mouth edge does NOT project beyond the bases of the vibrissae<\/figcaption><\/figure>\n

When working with material that has come out of alcohol do remember that the drying process can sometimes distort the shape of the head. It is not uncommon for the face to shrink a bit and buckle, causing a crease to develop in the face and for the mouth edge to appear projecting when it isn’t … use careful judgement in these cases.<\/p>\n","protected":false},"excerpt":{"rendered":"

One of the most awkward questions that you are asked is to judge whether (when viewed laterally) the mouth edge is projecting beyond the base…<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":822,"menu_order":0,"comment_status":"open","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-775","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"http:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/pages\/775","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"http:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"http:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/comments?post=775"}],"version-history":[{"count":20,"href":"http:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/pages\/775\/revisions"}],"predecessor-version":[{"id":780,"href":"http:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/pages\/775\/revisions\/780"}],"up":[{"embeddable":true,"href":"http:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/pages\/822"}],"wp:attachment":[{"href":"http:\/\/tachinidae.org.uk\/blog\/wp-json\/wp\/v2\/media?parent=775"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}