In the sentence extracted from biomedical literature, identify all the chemical entities. The required answer format is the same sentence with HTML <span> tags to mark up specific entities. 
### Entity Markup Guides:
Use <span class="chemical"> to denote a chemical.

### Input Text: Electroencephalographic and behavioral monitoring revealed a profound reduction of the threshold for pilocarpine - induced convulsions .
### Output Text:
Electroencephalographic and behavioral monitoring revealed a profound reduction of the threshold for <span class="chemical">pilocarpine</span> - induced convulsions . 