Starting with your organic forms with contour lines, you're doing a pretty decent job here - I just want to draw attention to one little thing. When you've got the end of a sausage pointing towards the viewer, it helps a lot to add a little contour ellipse right at the tip to really drive the idea home that it's facing the viewer. You can see this back in this step of the exercise demonstration.

Moving onto your insect constructions, it's clear to me that you show a lot of growth and development over the course of this lesson. You've worked very hard to apply the things covered in the lesson, and with each successive drawing, you show a stronger grasp of the relationship between the forms you're constructing, and a better grasp of how they all come together to create the creatures you're studying.

I can see you clearly making good use of the sausage method throughout (something many students seem to ignore to varying degrees), and while early on I can see some cases where in this dragonfly's head you cut back into the original mass's silhouette (instead of treating it like a solid mass), as you push later into the set you show a much stronger respect for the solidity of each form you add.

There are just a few things I want to suggest, or bring to your attention to help you continue improving.

First, a minor point. For that same dragonfly, when drawing its wings, I'd probably use the leaf construction process from lesson 3, as it's a flat form. I'd establish a flow line (though perhaps a bit more stiff than a normal leaf's) with a very simple silhouette, then I'd cut a little into that silhouette to add that little bend along the side of the wing.

Secondly, the legs of our insects can definitely get quite a bit more complicated than the sausage method allows on its own - that's entirely normal, and I'm very pleased to see that you still started out with the sausage method before attempting to build the greater detail on top of it. I have a few suggestions on how you might go about approaching this addition of greater detail in the future.

Firstly, one strategy is to build up additional forms, wrapping them around a given sausage structure as shown here. This is a little more effective than just enveloping a sausage form with a larger form, because 'wrapping' a form around actually creates a more direct relationship between the form being added, and the structure beneath it. You can see this same kind of approach being used in a few cases here. Taking it to its fullest extent however, you can build up many different such additional forms as shown on this ant leg, and it can even be used on animals, like this dog's leg.

For situations where you've got little spikes, serrations, or other such smaller details, the same kind of "wrapping around" of forms still applies, just a little differently. As you can see in this crab claw demo, the base of those serrated sections wrap around the rounded surface of the claw, while the top retains its spiky form. This kind of thing could be applied on the leg of this golden beetle. There (along the left side), you experimented with adding little spikes, but these were actually just flat, 2D shapes rather than actual 3D forms, so it didn't come out as believably.

Aside from that, your work is coming along great. I'll go ahead and mark this lesson as complete.