First we observe and analize real bugs and toy bugs: we discover some characteristics and discuss a model to classify the bugs according to the number of legs, wings or not wings, shell, body parts (head, thorax, abdomen) ...
Then we classify them into insects, arachinds and molluscs in a very visual way. You can see the outcomes of this part of the project in this Power Point.
Finally, after oral practise using the main vocabulary and basically two grammar structures ("has got" and "it is"), the children made a description of their favourite bugs. In this Power Point you can see some of the descriptions they made.
You can have a look to this reference: "Categorizing and classifying animals", an article by Judy Haynes in everythinESL.net for further support in planning a project like this.
In this project we are moving from level 1 to level 4 in the Bloom's Taxonomy adapted for English Language Teaching in Primary Education: identifying, categorizing and classifying, making models, describing... are some of the cognitive activities involved.