Modelling and UV-ing with modo: Modo layout: 301 default layout

First, choose a Layout in Modo for modelling: Layout menu/Layouts/301 Default Layout. From Tabbed Viewport Groups select the Model Quado tab. Load the reference drawings to the top, front and right viewports as backgrounds: second button on the top of the active viewport/Backdrop/Load Image... Editing the backdrop: the second button on the top of the active viewport/Backdrop/Properties/Background Imagery/Adjust Background Image.

Using the backdrops model the spiders body starting with a box and using extrude. (Creating a box: Shift+LMB click on Tool Tab Box icon.)

CLICK TO ENLARGE

The tools of the modelling can be chosen from the column to the right of the Tools Tab.

CLICK TO ENLARGE

For symmetric modelling enable symmetry for the appropriate axis on the Tool Tab.

Create the legs extruding them from the body.  It's enough to model one leg, then use that as a base for the other legs. Copying the leg, and forming the other legs: select the polygons of the legs in polygon mode then copy them. Create a new mesh on the Items palette, and paste them there to get a mesh, which you can move to the correct position. Form a hole on the spiders body to where you can fit the legs, then snap the legs vertices to the hole. Configuring snapping: The horizontal Toolbar/Snapping/Geometry.