Starting with your organic forms with contour lines, you're doing a decent job of sticking to simple sausage forms (although a few get just a little pinchy through the midsection). I did however notice you've been drawing your contour lines with the same degree throughout their lengths. As discussed back in lesson 2, these contour lines should be getting wider as they slide away from the viewer, as shown here. The contour lines' degree represents the orientation of that cross-section of the form, relative to the position of the viewer.

Looking through your insect constructions, I'm definitely seeing a fair bit of improvement over the set, but there are some issues I want to call out.

The first one actually doesn't show up too often, but it's important enough to warrant a fair bit of attention. Taking a look at this planthoper, you ended up drawing the thorax pretty big. Since the ellipse was a bit loose, you opted to use the inner one to bring that size back in a bit. Unfortunately, this leaves lines outside of your ball form, which doesn't really work so well. The viewer is free to still interpret the ball as extending out to its largest size, which is already being cut into with the legs, resulting in weird visual contradictions.

Now, the problem of basically cutting back into the silhouettes of your established forms, (like how the planthopper's thorax mass was cut back is one that should be avoided, for the reasons explained in these notes. Any kind of modifications to the silhouettes of forms that have already been constructed should be avoided - including extending or adding to a silhouette. Every addition should be done using a new, complete form added to the construction, with the way it relates to or intersects with the existing structure defined (for example, with contour lines).

The core of construction really is that - the idea that we establish our simple forms, and then build right onto them, ideally clearly establishing how the added forms actually wrap around the existing ones. So while you did build on top of the thorax in this insect, it kind of lacked a sense of how the segmentation you added really wrapped around it. Here's an example of what I mean.

On this praying mantis, we've got plenty of cases where you've tried to add little spikes/spines using simple 2D shapes. These are essentially what I meant by 'extensions' of the silhouette, where you've added a flat shape instead of establishing a complete 3D form, and its relationship with the structure. Conversely, here's an example of a beetle's horn where it is gradually built up with forms that are each fully enclosed, then attached to what is already present. You can also see similar approaches to combining forms in this ant's head.

Another thing worth noting is that on both these insects, both abdomens featured very shallow, poorly drawn contour lines. Here you did not hook the contour lines around enough at the edges to properly give the impression that they were wrapping around a rounded form. Overshooting your curves a little as discussed here will help with this.

A minor point about this insect - reserve your filled areas of solid black for cast shadow shapes only. That is, the ones cast from one major form onto another, or from one textural form onto its surroundings. If you find something has dark stripes or spots or some other kind of darker local colour, ignore it and treat it as though everything is coloured the same flat white. Our focus is on information that exists in 3D space - things we can touch and feel with our hands and fingertips.

Another minor, but still worthwhile point I wanted to call it is that it is very, very important you establish the connections/intersections/relationships between forms. We can do this by placing contour lines right at the joint between forms, as shown here.

It's actually a huge part of the sausage method, and one that you do miss a fair bit. I can see that you are at times attempting to employ it, but not as consistently as you could. It's not uncommon for students to be aware of the sausage method, 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. 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.

While I am overall pleased with your growth, I would like to see a few more drawings where you employ the principles I've mentioned here. So, I'll assign a few pages of revisions to give you the opportunity to demonstrate that you understand.