Starting with your organic forms with contour lines, you're doing a decent job here - your contour lines themselves are looking decent, though you are largely repeating the same degree for each curve along the length of a form. Remember that as you slide away from the viewer, the curve's degree should get wider. Looking at the sausage shapes themselves, you're pretty close to maintaining the characteristics of simple sausages although there is a tendency to let one or both ends get a little more stretched out, rather than keeping them entirely circular.

Moving onto the insect constructions, while in some areas you do demonstrate a developing understanding of 3D space and form, there are a number of issues that are getting in the way of that. Hopefully addressing them should help you improve your results a good bit.

The first, and definitely one of the more significant issues is a relatively simple one - drawing small tends to result in clumsier linework by limiting the brain's capacity to think through spatial problems, and by making it harder for you to engage your whole arm while drawing. Some students will draw smaller because they want to really fill up their pages - while this is still not great, you appear to be just drawing smaller for the hell of it, leaving a lot of blank space on each page. What matters most is that you make use of the space that is available to you. Focus first and foremost on giving each drawing as much room as it requires. Once it's done, you can assess whether there is enough room left over for another. If there is, add another, but if there isn't, it's okay to have a page with one drawing. Situations like this page where you've got loads of free realestate for more drawings should absolutely be avoided. Two drawings to a page is totally fine, but both of those should be way bigger.

The second issue is that you're forgetting some relatively basic principles of construction, and basic rules presented in previous lessons. Draw every form in its entirety. Don't cut them off where they get overlapped by another. This simply cements them as flat shapes, rather than 3D forms. A form continues to exist where you can't see it anymore - even if and especially if it's being interested by another form. Drawing both forms in this case and then defining the relationship between them with a contour line is an important part of building up that 3D illusion. Also, draw through your ellipses 2 full times before lifting your pen, as introduced back in lesson 1.

The third issue I want you to keep in mind is that once you draw a form, you shouldn't be modifying its silhouette. Often students will do this in an attempt to refine the form, or add more complexity, but it's a shortcut that will end up flattening out your construction. I can see you doing this in a couple different ways in the ant drawing on this page. When drawing its abdomen, you started with a larger form, then drew two smaller ones inside of it. As shown here, cutting into the silhouette of a form with the expectation that the viewer's just going to ignore the bigger one simply doesn't work. Once you try to alter the silhouette of a form, it doesn't change the form itself - it merely breaks the connection between the two, leaving you with just a flat shape. This also happens when we try to extend a silhouette, as you did with the ant's head.

Instead, we build upon the existing construction by adding new 3D forms to the construction. We either have the silhouette of this new form wrap around the existing structure, or we define how the two forms intersect using contour lines. You can see this at play in this beetle horn demo, in this ant head demo, and in a number of ways throughout this more detailed lobster demonstration.

Speaking of contour lines, I noticed that you have a tendency of employing a lot of them in some situations, like with this beetle. The contour lines were honestly drawn pretty sloppily, but in general it's very important that you keep in mind that contour lines - specifically the ones that sit on the surface of a single form - suffer from diminishing returns. Using a ton of them just for the hell of it doesn't really work all that well. Instead, you need to be strategic about how and where you use them, ensuring that they're drawn to the best of your ability, and that they're serving an actual purpose. Piling on more and more won't actually yield a better result. Instead of using them in this kind manner, they tend to be most effective when defining the relationship between different forms in 3D space.

The last issue I wanted to call out is that I noticed that you seem to have employed a few different strategies for capturing the legs of your insects. It's not uncommon for students to be aware of the sausage method as introduced here, but to decide that the legs they're looking at don't actually seem to look like a chain of sausages, so they use some other strategy. In your case, I think you were attempting to employ the sausage method, but ended up using ellipses instead of sausages in some cases, or in others just didn't adhere as closely to the 'simple sausages' as you should have. Sticking to simple sausages and ensuring that you define the joint between them with a contour line are important parts of the technique, so make sure you do so consistently.

Going beyond that, the key to keep in mind here is that the sausage method is not about capturing the legs precisely as they are - it is about laying in a base structure or armature that captures both the solidity and the gestural flow of a limb in equal measure, where the majority of other techniques lean too far to one side, either looking solid and stiff or gestural but flat. Once in place, we can then build on top of this base structure with more additional forms as shown here, here, this ant leg, and even here in the context of a dog's leg (because this technique is still to be used throughout the next lesson as well). Just make sure you start out with the sausages, precisely as the steps are laid out in that diagram - don't throw the technique out just because it doesn't immediately look like what you're trying to construct.

Now, I've shared a number of things for you to work on here, but I think that having had these pointed out, you should be able to do much better. I'm going to assign a few additional pages of revision. If you've had quite enough of insects, you are allowed to study some crustaceans instead.