Fortunately your question of line weight is something I was planning on addressing in your work, and I'll be sure to talk about the sausage thing as well, as it's not an uncommon thing students struggle with, especially at smaller scales. As a whole though, your work (the more experimental things like the bee/wasp where you went to town on it with the brush pen aside) is all largely well done. There are some issues I'm certainly going to address, most related to how you try to approach matters relating to line weight, and just the mentality with which you're approaching certain aspects of your drawings, but all in all when it comes to the main concepts covered in the lesson, you're doing a good job.

That is especially in relation to your understanding of spatial relationships between your forms, and how everything exists together in 3D space.

Starting with your organic forms with contour lines, you're largely doing a pretty good job here. Some of your forms aren't entirely adhering to the 'simple sausage' characteristics outlined in the instructions, but most are quite close. I figure this is probably the best time to talk about how to approach getting those simple sausage shapes down properly. All things considered, I don't actually see any notably problematic issues here, but the you were struggling most of all with smaller sausages, which again is totally understandable.

Aside from the true statement that "it'll get better with practice", and the observation that throughout your insect constructions when you do draw those kinds of sausage forms, they come out pretty well (not perfect, but looking at things like the praying mantis they're a bit off especially for the longer ones but that's pretty normal), I do have one suggestion I can give. When it comes to the ghosting method, students are told that the execution of their marks need to be confident. They're purposely not told that the executions need to be fast. For most beginners, confident inherently means that they have to draw quickly, as that is the only way they can avoid the kind of hesitation that makes their linework wobble, but as you get more practiced with the ghosting method, the speed you need to maintain in order to avoid those wobbles actually decreases. So, my suggestion is that you try to let yourself slow down a little. Be careful, we still don't want to see any wobbles, hesitation or stiffness. The key is to continue drawing with confidence, but to do so with a slower pace, so that your arm can reclaim a little more control over the stroke. This will make rounding the ends of your sausages a bit easier.

Now, looking over your insect drawings as I mentioned before you do demonstrate a strong grasp of how your forms fit together, and how they all exist together in 3D space. There are a couple main issues that I want to address that will help you improve your approach for constructional drawing.

Firstly, every addition to a construction needs to itself be a solid, 3D form. If you look at the ends of your praying mantis' thorax, you'll notice how once you drew in a simpler form, you then went back and kind of extended out its silhouette to flare either end. This kind of adjustment is something you did to the two dimensional silhouette, and as such, it is a little sign that this drawing is itself just a bunch of flat lines on a flat page. Instead, we want to add this kind of detail by piling more forms on top, as shown here, wrapping them around the underlying structure.

We do the same thing with the sausages when employing the sausage method for constructing legs. Most legs don't look like a chain of sausages (and this may often cause you to deviate from the strict rules of the sausage method explained here). The key is that we're not drawing the whole leg right off the bat - what we're doing is laying down an underlying structure or armature that accomplishes two things: it captures the illusion of solidity, and captures the sense of gestural flow for that limb. Usually leg-drawing techniques focus on one or the other, appearing either solid and stiff, or gestural but flat. This allows us to accomplish both. Once we've done that, we can then wrap additional masses around those forms, as shown here and along the bottom half of this diagram.

Construction is all about starting simple and solving the core problems, and then gradually building things up. You generally do show an understanding of this, but there are places where you jump more into complex too soon, like the praying mantis' arms, which have larger areas of bulk and more irregularity to their shapes.

The second point I wanted to touch upon is, of course how you approach line weight. You've done a great deal of experimenting throughout this lesson, and there are places where you've employed line weight pretty well, and others where you've not been as successful. The praying mantis is, for the most part, well done. The only issue is that the linework for the head is quite sketchy and rough.

This kind of sketchiness at times leads you to try and seek to replace your linework (usually using line weight all over the place, instead of at just key areas). It's not uncommon for students to think of their drawings in terms of a "rough underdrawing" and then a "clean-up pass", where first they're allowed to think through their problems, solve them, then go back over them to draw the "real" clean lines. That is not what we do however, as part of the constructional drawing process.

Instead, in constructional drawing as an exercise, we treat every single mark we draw as though it is part of the final drawing. Not to be hidden or covered up - it's there, and at the very least it serves as a solid form upon which more detail and information is built up. To this point, we use line weight sparingly. We never apply line weight to the entirety of a form's outline, as you did plenty of with the scorpion. Nor do we add line weight to be very heavy and obvious. Line weight is specifically used to be subtle, as I often say to students it's about whispering to the viewer's subconscious, that one line is slightly heavier at a point than another, not screaming in their face.

For this reason, I always push students to use the same pen throughout the entirety of their drawing, only using a brush pen or something thicker to fill in shadow shapes (which would ostensibly already have been outlined). Often times students can get confused between line weight, which as mentioned is subtle, with cast shadows. Cast shadows can be as broad and heavy as we need them to be, but there's a clear difference - cast shadows fall on the surface of a different form. They don't cling to the silhouette of the form that casts them, and they don't float arbitrarily in the air. So where we see really thick line weight along the side of the scorpion's tail, there's no reasonable way for that to be a cast shadow since there's no surface for it to fall upon. Therefore we're limited to very subtle line weight there, and only where we want to clarify how certain forms overlap others - not reinforcing the entire line as a whole.

The last thing I want to mention on this point is that obviously while this bee was an experiment, as a rule reserve filled black shapes only for cast shadows. If you see a pattern on something, or anything that appears to have a "local colour" of black (basically the colour of the surface when all lighting information is ignored), don't try to capture that just because you're working with a black pen. Treat it as though the whole object is the same flat grey.

With that, I'll go ahead and mark this lesson as complete. I've certainly given you a number of things to think about, but you can certainly keep them in mind as you tackle the animals in lesson 5. Remember that the points I mentioned about the sausage method also apply within lesson 5, even moreso do to the complexity of their legs.