The thing to figure out is what kind of environment you want your species hailing from.
Skep155 is totally right to point out that a high-gravity environment would be deadly to an insect species. Ways to ameliorate this, however, are extremely high O2 content in the air and/or very efficient O2 extraction mechanism for lungs, but ultimately a human-sized arthopod is going to likely need to be from a less-than-1G world.
I'm doing a story in which there is a Horta character, which has compelled me to think of how their society would be. It has significant insectoid qualities, particularly in that in any given Horta colony, only one individual expresses female sex characteristics and lays eggs. Surely she doesn't communicate with her thousands of children by sound, either. Nor can she communicate visually, in the darkness beneath Janus IV--in all likelihood, the Horta are quite blind. A sophisticated language of pheromones supplemented by braille-like script in their tubes, however, would be sufficient and plausible.
Now I just have to work out how silicon based pheromones work. I know of no silicon compound that is a gas at anything approaching room temperature.
The point is, think about its habitat, and you should be able to convincingly describe its traits.