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21 April 2018

21 April 2018 – March Dagger

(Diurnea fagella)

The first trap of 2018 was set following the hottest April day for many years – however the overnight temperature had dropped considerably and when I went out at 6am this morning the dew had saturated the lawn with an icy coldness and expectations were low. Visitors were due to arrive mid-morning and introducing moths and moth-trapping to a new audience having only Clouded Drabs, Hebrew Characters, Yellow-line Quakers and Early Greys as examples might not demonstrate why this caper is so interesting.  Fortunately, to the discerning eye, an Early Grey is a thing of beauty and so it was to the guests.  Four Early Thorns added welcome variety and then, lurking at the bottom of the trap, one that was unfamiliar. 

I went through all of the photographs on this blog to see if I could see one already recorded.  The head and upper thorax was as black as pitch and I began to wonder if it was a moth and not a sawfly or a species of caddis.  The Lewington guides were riffled through as was the Yorkshire website but I couldn’t spot its like.  Fortunately an email to Charlie Fletcher was responded to and the moth was identified as a poorly marked Diurnea flagella the ‘daylight-flying, lover-of-beech-trees’.   

(Diurnea fagella)

Humphreys and Westwood in British Moths and their Transformations Vol 2  has the moth on Plate 110 and there (above) can be seen the standard variety (fig 9), the larger variant (fig 10) and the female (fig 11).  The description informs the reader that the female of the March Dagger (as it is described) is smaller than the male but it doesn’t record that she is flightless.  The wings are somewhat short in the illustration but the moth is unquestionably airborn so perhaps her restrictions were not common knowledge.

March Dagger is species number 426