Alrighty, last critique of the day! Even though it technically came in past my noon cut-off, but I've still got some time before midnight, so let's get to it.

Starting with your organic forms with contour lines, these are honestly not as good as I know they could be. You're definitely aiming to keep your sausages simple, but you're not quite adhering to the characteristics listed here in the instructions. Specifically, we want the ends to be circular, and the midsection to remain consistent in width. Sometimes you're closer to that, but you've got quite a few that deviate a fair bit.

When it comes to drawing those sausage forms, slowing down a little bit (whilst still continuing to draw confidently, without hesitation), and drawing always from your shoulder should help.

The contour lines themselves are a bit of a mixed bag - you do need to think more about the degree you want to draw them at, corresponding to that cross-section's orientation relative to the viewer, and using the ghosting method as you would for any other mark will help you meek them snug between the edges of the sausage forms.

Now, I'm going to skip on down past the demo drawings and focus on the ones you did entirely by yourself. While there are a few issues I'm going to point out, as a whole you are definitely moving in the right direction with these, focusing mostly on how you can combine solid, three dimensional forms with one another to create more complex objects that remain believable.

The first thing I want to correct you on however are the instances where you've tried to add certain details/elements by redrawing (either by extending or cutting back into) the silhouette of an existing form. A good example of this can be seen on this beetle.

Here I've pointed out a number of such issues. The one that I shaded in, towards the front of the thorax area, is an example of you cutting back into the silhouette, while the others are all adding shapes to the silhouette of forms after they've been drawn. The easiest way to explain why this is a mistake is to look at how cutting into a silhouette flattens the form out.

Basically when we draw a form, we're left with a 2D shape on the page (the silhouette) which represents that form. Changing the silhouette doesn't change the form itself, as it exists in 3D space - it simply breaks the relationship between them, leaving us with a more obviously flat shape. The way to avoid this is to add the spikes and other such features as their own separate, complete 3D forms. You can see an example of this with this beetle horn demo, and even on this ant head demo.

Construction is all about building forms on top of forms, and either wrapping them around the existing structure or defining how they intersection in 3D space to create clear relationships between them in the 3D world, rather than on the flat page.

Another issue that I'm noticing is that you're kind of treating your drawing as though it can be split up into two separate parts - an underdrawing/construction, where you're drawing more faintly, and then a phase where you go back over your lines with new, darker lines. Remember that line weight doesn't involve going back over whole lines and shapes. Line weight is just about clarifying the overlap between forms in specific, localized areas. It's applied confidently, using the ghosting method, and by drawing confidently our marks taper, allowing us to blend them back into the original linework as shown here.

So what you should not be doing is tracing back over your lines to create a separate clean-up pass. Tracing over lines tends to cause us to draw more carefully and hesitantly, focusing too much on how those lines exist on the flat page, rather than how they represent edges and forms that exist in three dimensions.

The last point I wanted to make is that I noticed that you seem to have employed a lot of 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. 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, with that all laid out, I still think you're largely employing construction fairly well - especially in drawings like your praying mantis at the end there, which while simple, clearly is established as a series of simple forms all connected to one another. So, I'll go ahead and mark this lesson as complete.