Overall, very well done, with a few minor things to point out. Starting with your organic forms with contour curves, my only concern here is that the sausage forms themselves aren't entirely adhering to the "simple sausage form" characteristics outlined here. This simple formula of two equally sized spheres connected by a tube of consistent width helps a great deal to ensure the forms feel solid and three dimensional, even with minimal contour lines. You're obviously aware of this however, and are getting pretty close - just need to keep an eye on the ends of your forms for the most part, where they tend to get a little stretched out instead of remaining entirely spherical. There are also a few places where you get a bit of pinching when your sausages turn.

Moving onto your insect constructions, there's a lot of good here. For the most part you're applying constructional principles quite effectively, building upon simple combinations of forms to gradually add complexity as you go. You're also generally respecting the fact that every mark you put down on the page adds a solid, three dimensional form to the world (something that cannot simply be treated like it's a shape on a page) aside from a couple places.

One such place is on the abdomen of this spider. Most of this spider - head, thorax, and the first few segments of each of its legs - were exceptionally well done. Something that stands out however is that you'd established a lighter space for the abdomen to occupy, but ended up drawing a much narrower form with a darker line. It's possible that the lighter, wider ellipse came next, but ultimately it doesn't really matter. What we see here are two potential forms occupying the same space, and this creates contradictions that undermine the illusion of solidity in your drawing.

When drawing, we want to avoid these kinds of contradictions - we can build on top of forms we've put down, and we can cut back into them as shown here (where you separate a form into two separate 3D entities using contour lines), but we cannot simply choose to jump between treating them like 3D forms, then 2D shapes, willy-nilly. We have to stick to constantly reinforcing the illusion that everything we draw is solid and three dimensional.

To the point about the legs, those first two segments on each one look great, but once the sausage segments get really narrow, it becomes considerably more difficult for you to maintain the 'simple sausage' form. Some of them end up being more like stretched ellipses, others pinch arbitrarily through their sections, and others still have stretched ends. This is fairly normal, in that the narrower they get, the more difficult they are to draw, but it is something to keep an eye on and continue working on.

To this point, there are a lot of places you're clearly trying to adhere to the sausage method when constructing your legs, but it's not always consistent. While there may be cases where you feel the leg you're looking to draw doesn't match the appearance of a chain of sausage forms, don't think in terms of what matches the look you're going for, and instead think of it as though you're setting down an underlying structure or armature. We can always build upon it as needed after the fact as shown here, but first and foremost we want to make sure we have something that captures both an illusion of solidity and a sense of gestural flow for the limbs. For this, the sausage method is just about always the right choice, and will continue to be through Lesson 5 when we get into animals.

The last thing I wanted to mention is a simple point - you've got a couple cases like this one where you've drawn segmentation along the abdomen, but didn't draw it where it was overlapped by the wings. Draw through your forms - this means, draw them as though you have x-ray vision. It will help you establish the full relationship between that form and the rest of the constructions as well as space as a whole. In this particular case, the segmentation to wrap around the abdomen as you would with your contour curves exercise will ensure that their curvature is correct.

So! All in all, good work, with a few things to keep an eye on. I'll go ahead and mark this lesson as complete.