Hi
It could be very confused to base the determination of a larva only by the pictures or by few features.
The determination is also greatly dependent on the land area where it is detected and observed.
I have had many difficulties to determine this larva as there is a light possible confusion in the litterature
Spiracular libes and anal region
first source : Theowald 1967
second source: Lantsov,_1999b Tipulidae in Tsalolikhin
and as the setae position were in the same place as defined by Smith reference,
Then I propose Tipula obscuriventris to give this larva a name
the difference is in the fact that Tipula saginata is only found in Alpine regions and in North of Italy...
In the video, please pay attention to the two larvae, there is one bigger than the other
In this bigger habitus, there is a surprise ... I will explain and elaborate more fully in a later post
These larvae were respectively 40 et 55 mm length and collected in a freshwater river in Haute Ardenne, Belgium