Who said identifying grasshoppers is easy? The mottled grasshopper (Myrmeleotettix maculatus) can be extremely variable in colour and the males especially can be confused with common field grasshopper and the rare heath grasshopper. To make matters worse, the mottled grasshopper is most frequently found in similar habitat to these two look-a-likes! The females can be quite striking with white patches on a green background and if you encounter one like this they are quite unmistakable.
Whilst the mottled grasshopper is the smallest species in Dorset it is not possible to identify them on size alone! The most distinctive feature of this species, and one that tells it apart from its similar cousins, are the clubbed tips to the antennae. If you can get a good enough view and can see the antennae appear swollen at the end then you have, indeed, found a mottled grasshopper.
Far from common, you are most likely to find this species on dry heathland, especially in the Poole basin and eastern Dorset.