Challenge 39 is Seiji Nishikawa’s 15° Oriential Longheaded Locust.
I’ve covered quite a few Nishikawa’s models due to him having so many crease pattern challenges. I’m sure there are quite a few I’ve missed, but I’m not sure which I’ve put up here and which I haven’t. It probably would have been better to put the second half of Origami Insects Vol. 1 here (instead of with Challenge 14) as this Challenge immediately follows a Kawahata one that I put the first half with. But I didn’t do that. Oops.
Anyway, this is a nice model with an interesting design using fifths and equilateral triangles. Not my favourite bug tho.