Insect setting beagle test (4,6)
I believe the answer is:
stag beetle
'insect' is the definition.
(stag beetle is a kind of insect)
'setting beagle test' is the wordplay.
'setting' is an anagram indicator.
'beagle'+'test'='beagletest'
'beagletest' anagrammed gives 'STAG-BEETLE'.
(Other definitions for stag beetle that I've seen before include "something some folk find creepy" , "Six-footer" , "Large insect with branched mandibles" , "Insect with antler-like jaws" , "Horny little creature" .)