Starting with your organic forms with contour lines, these are looking solid. There are a few cases where you stray from the characteristics of simple sausages, but generally they're looking good. Do remember though that as the contour lines slide further away from the viewer, they should get wider.

Continuing onto the insect constructions, there's a lot of good here. There are a lot of places where you're showing a clear grasp of how your constructions are made up of solid, three dimensional forms. There are however some key ways in which you undermine that illusion, so let's take a look at resolving those issues.

First and foremost, you have a tendency of starting your initial masses with a fainter, less committed line. We can see this for example in this wasp where the cranial mass, thorax and abdomen are visibly lighter, but everything that follows is much darker. Avoid doing this - it tends to make us treat those initial forms as being not-quite-real, which makes us more susceptible to ignoring them or cutting across them freely.

This brings us to the second point - once you've added a form to the world, do not change its silhouette. Sometimes students will cut back across a form's silhouette, or extend it to "refine" its shape. Unfortunately this doesn't actually change the form itself - it merely breaks the connection between the 2D shape that represents it on the page, and the form itself, leaving us with just a flat drawing. As you can see here you did cut across your forms a bit in the wasp drawing, and you also used some 2D shapes to add the little spikes on his legs. There are some others that I didn't bother to highlight there.

The problem with this is easiest to understand when looking at what happens when we cut back across a form's silhouette. There are of course ways to cut back into a form correctly, but this is better suited to geometric construction rather than the organic stuff we're doing here.

Instead, we need to be working additively, introducing a new solid, complete, enclosed 3D form for every change we wish to introduce, and then defining the intersection between it and the existing structure with a contour line (like the lesson 2 form intersections) or crafting the new form's silhouette to specifically wrap around the existing structure. You actually do this correctly in a bunch of places, like this beetle's legs where you've wrapped little bits of segmentation around the sausage structures.

You can also see this at play in this beetle horn demo, this ant head demo (which you should look at closely, as it should help you when dealing with your insects' head constructions), and in this more detailed lobster demo.

Aside from that point, I am quite happy with the rest of your work. You're doing a great job of employing the sausage method, and while there are definitely some drawings where you could build on top of that sausage structure a lot more (just need to observe your reference more closely to identify the smaller form details that are present, like in this ant leg demo). You'll be using this same technique throughout Lesson 5 as well.

So! All in all, very well done. I'll go ahead and mark this lesson as complete.