Using the following script with cmaple I got a plot with three legend elements. (see img link). 

How can I remove Curve 3 and Curve 5 entries?

with(plots):
plotsetup(gif,plotoutput=`test_maple.gif`,plotoptions=`color,noborder,portrait`):

l:=10^(-3);
Vel:=(y,t)->sum(n*y*t, n = 0 .. 10);

Vel1 := plot(...