Starting with your organic forms with contour lines, I suspect you may have jumped into this without actually looking back at the instructions for the exercise. There are a few issues that stand out:

• You're not consistently adhering to the characteristics of simple sausage forms

• You're struggling to get your contour curves to hook around enough as they reach the edge of the silhouette, causing the sausages to get flattened out. Overshooting your curves as explained here will help.

• The degree of your contour lines are either remaining the same throughout the length of your sausage forms, or showing the opposite behaviour that they should. Contour curves should be narrower when closer to the viewer, wider when farther away, as shown here.

Moving onto your insect constructions, while there are definitely some areas of strength and growth, there are also a number of key issues that aren't quite lining up with the approach you're meant to be using throughout this course. I'll address each point separately below.

The principles of constructional drawing

First and foremost, the most important thing about what we're doing here is the mentality that goes behind constructional drawing. Constructional drawing is, at its core, an exercise. So we're not focusing on creating pretty drawings in the end, just in what we can learn about 3D space and the relationships between forms.

Every single thing we add to a construction is always going to be a solid, three dimensional form. It's like introducing a solid chunk of marble into a world. Once it's there, it cannot be ignored, treated like it's not present, or somehow replaced. We can only ever build on top of it (by introducing yet another form and defining how it either wraps around that existing structure or how it intersects/connects with it).

So, looking at this wasp's head for instance, you started out with a ball form that you drew quite lightly, and then ended up drawing an entirely different shape/form on top of it, cutting across its silhouette as though it wasn't there. This introduces a contradiction to your drawing, where the viewer is faced with two potential forms that exist in the same space, independently of one another, with no clear relationship between them. Contradictions undermine the viewer's suspension of disbelief.

Don't modify the silhouette of forms you've already established

Now, what you trying to do here was to modify and adjust the silhouette of this form you'd already drawn. Unfortunately, the silhouette of a form is just a 2D shape. It represents a 3D form, sure, but if you change the silhouette it does not change the form - it merely destroys the illusion that it was ever a form in the first place. As such, we don't ever make changes to the silhouettes of these simple forms - we build new forms on top of them, as mentioned earlier.

Here's an explanation as to why cutting back into a silhouette flattens out your drawing, and it applies equally to extending a silhouette. These are all just actions occurring in 2D space, so they don't serve to change the 3D world we're trying to get the viewer to believe in. As mentioned in that diagram, while there is a correct approach to 'subtractive' construction, it's better left for geometric and hard-surface subject matter. For organics, working additively is best. You can see examples of this with this beetle's horn and this ant's head.

Overuse of contour lines

I did notice that you have a bit of a tendency to overuse contour lines. This happens most often when students aren't necessarily thinking about what they're trying to achieve with the marks they're introducing to their drawings - instead, since you've learned about contour lines as a useful tool, you're just falling into a rhythm, adding lots of them because you feel that's what you're probably supposed to do. The key is to get in the habit of thinking through each and every mark you draw, assessing just what it is meant to contribute to a drawing.

Contour lines - specifically those that sit along the surface of a single form - suffer from diminishing returns. The first may have a significant impact, the second much less, and the third even less than that. Piling on more and more doesn't help, and more often students will sometimes put less effort into each individual because of the quantity they're adding instead. That of course makes things worse.

Looking at this wasp again, the abdomen is totally fine - the contour lines relate to the specific segmentation, so they serve a purpose. The contour lines on the head and thorax however, don't serve any real purpose.

Now, not all contour lines are equal - those that define the intersection/relationship between forms are extremely effective - and so focusing instead just on those first and foremost will generally yield better results. Then, in the odd situation where you don't feel a form feels three dimensional enough despite those joints being defined, you can add one purposefully planned contour line and see how it goes.

Ignoring a lot of complexity

This one's not an uncommon mistake by any stretch - insects' bodies are pretty complex. They have all kinds of segmentation, arranged in very specific ways that we can identify by studying the reference images. Of course, the first step is to build those forms up focusing only on the simple masses, as you have done. But once that's in place, you're not finished. You then go in and wrap further segmentation around the masses you've already built up. Here's an example with another student's dragonfly - pay attention specifically to the quick drawing I did of the thorax/legs area.

Don't trace back over your drawings

I'm definitely noticing a tendency to split your drawing between 'underdrawing' and 'clean up pass', especially where you end up with most of your drawing being replaced with heavier, darker lines all over. Line weight is meant to focus only on key, localized areas, clarifying specific overlaps. It is not meant to help you recreate your drawing by tracing over construction lines.

If you look at my demonstrations, throughout the whole process I don't go out of my way to make any lines darker than any others until the very end, when I start clarifying those overlaps.

As a side note to this, remember that all filled areas of solid black should be reserved only for cast shadows. If your insect has something like black eyes, don't fill them in. Treat everything like it's made of the same flat white colour.

Also, I saw some little areas where you were adding a lot of line weight on one side of a form (like this beetle's feet), which looked like you were trying to replicate form shading. Don't forget that as discussed back in lesson 2, we do not get into any form shading in this course.

Legs

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.

Conclusion

So, I've laid out a number of areas where we can stand to improve your work. I'll go ahead and assign some pages of revisions below.