Overall, your work throughout this lesson is very strong and conveys a strong grasp of how the forms you're constructing exist within 3D space, and how they relate to one another. There are a few issues I want to address - one that is more fundamental and at the core of constructional drawing itself - but you're still doing a really solid job overall and should be proud of your work.

Starting with your organic forms with contour lines, you're doing a pretty good job with these, in terms of keeping relatively simple sausages (there's still room for improvement in sticking to the two-equally-sized-spheres-connected-by-a-tube-of-consistent-width recipe, but you're moving in that direction), and your contour lines are wrapping around the forms quite well. Do continue to think about how the degree of your contour lines represents the orientation of that cross-section as shown here though. I think your drawings suggest that you understand that, but sometimes your contour lines come out a little too consistent in their widths.

Moving onto your insect constructions, I think you did a pretty good job of following along with the demonstrations, and then went on to apply those principles really well to your own drawings. The core aspects of your constructions tend to have really excellent volumes, and clearly defined relationships between all of those forms in such a way that it really sells how each structure exists in three dimensions.

The first issue I wanted to point out however was that your adherence to the sausage method wasn't entirely consistent. You actually got really quite good at it in a few of these (like your leafhopper and your bumble bee, though in a couple places you forgot to reinforce the joint between sausages with a contour line). In the mantidfly, because you didn't see the legs as matching up with a bunch of sausages, you attempted to employ different approaches. The thing about the sausage method is that it still should be applied regardless of how the legs themselves look - and you'll find that we use them across the board in the next lesson as well (with animals).

This is because the sausage method is very effective at creating a base structure or armature that captures both a sense of solidity as well as a sense of gestural fluidity simultaneously. This is something that most approaches will achieve only with one or the other, resulting in legs that are very gestural but not quite solid, or very solid but rather stiff. Once we've established this armature, we can continue to build up on top of it as shown here, using additional masses that wrap around this structure to add bulk where necessary.

The other point I wanted to mention is visible in the scorpion most of all, but we can see it in very small parts along the bee assassin's legs as well. Basically, when drawing the scorpion, you followed along with the demo and drew a box as a starting point for the scorpion's body. Once the box was in place, you continued to draw the scorpion's thorax, but you did so in a way that seemed to ignore the presence of the box, or at best, treat it like a sort of suggestion.

Construction is all about respecting every single form we construct as being a solid form within our 3D world - something tangible, made of marble that cannot be simply ignored. Once established, such a form needs to be dealt with. You'll notice that in the demo video for the scorpion, I went on to cut into this box, separating it into pieces by drawing a line along the surface of the form, as though it was with a scalpel. This helped define the box as being separated into two distinct pieces in three dimensions. We were still able to understand how all these elements related to one another, and while one piece was treated as still remaining, the other was designated as negative space - an empty void.

Now, this is considered 'subtractive construction' and we use it very rarely, only when absolutely necessary. Most of the time, and whenever possible, we'll use additive construction - something you've employed quite effectively throughout this set. To put it simply, if ever you need to remove part of a form you've ever drawn, and there's no way around it, you need to first split it into distinct 3D pieces by drawing a contour line along its surface. I demonstrated this here in something I drew for another student some time ago.

Otherwise, we need to fully respect that these forms are present within our construction, and therefore need to be built on top of, rather than ignored.

So! All in all, your work here really is impressive. I will happily mark this lesson as complete. Keep up the great work.