truncate text in specific class

truncate text in specific class

Hi.  I'm using a WordPress plugin that returns date/time information like this, multiple times on a page:  

<div class="eventsdate">
   <span class="events-date-start">September 25 @ 9:30 am</span>
   <span class="events-date-end">September 28 @ 4:30 pm</span>
</div>

But I only want the date part.

how can Jquery shorten the two spans to just say September 25 and September 28? 

Thanks in advance for the help.