Thread subject: Diptera.info :: Trichocera hiemalis vs parva

Posted by pjoris on 19-01-2010 09:26
#1

From Bei-Bienko, I thought I could identify this one as T. parva - but now I'm not sure if it is not hiemalis. Any ideas or extra pointers to differences between the two species? Thanks, Joris

waarnemingen.be/fotonew/8/1029098.jpg

waarnemingen.be/fotonew/7/1029097.jpg
(The reason I thought it was parva is because the "thingies" in the middle (sorry forgot the name ...) are long and strongly curved which I read as indicating parva, rather than hiemalis.)

Edited by pjoris on 19-01-2010 10:27

Posted by Andrius on 19-01-2010 11:19
#2

Hi,
where and when was this insect collected?

Well, male hiemalis are easily distinguished by the fused gonocoxal bridge, usually forming an acute tip (indicated with arrows on the picture below). It also most often has an outgrowth on the ninth sternite (also indicated on the picture). It's a pity Bei-Bienko doesn't show that clearly. parva doesn't have the features indicated and the bridge is separated (see the second picture).

Edited by Andrius on 19-01-2010 11:20

Posted by Andrius on 19-01-2010 11:22
#3

And parva:

Posted by pjoris on 19-01-2010 11:34
#4

Great - thanks. T hiemalis it is:
waarnemingen.be/fotonew/9/1029099.jpg
I'm surprised about the gonocoxal bridge not being fused in parva - I distinctly remember it as a characteristic for parva in BB (unless I misread of course)

It is from Belgium (Leuven), 10-01-2010 (http://waarneming...w/46068505). I also had T major (http://waarneming...w/46042072) and T relegationis (http://waarneming...w/45811628) - I think ...

Thanks again,

Joris

Edited by pjoris on 19-01-2010 11:46

Posted by pjoris on 19-01-2010 20:47
#5

Ah - I did misread, it is described correctly in BB. I forgot the first rule of using a key: make sure you read everything and follow the right numbers ...