The June bug, field chafer coch-ybonddu are all names given to a beetle (Phylopertha horticola). It is a useful pattern effectice as early as mid-May if trout start feeding on beetles which you will discover by spooning the fish. As one of its common names implies it is found in large numbers around the month of June and is in greatest evfidence in the Celtic fringes of the British Isles. If fishing wilder parts of the country this fly is essential during the month of June
As the name indicates the dry fly which include Coch-Y-Bondhu are designed to float on the surface of the water. Coch-Y-Bondhu imitate a wide variery of flies and insects which inhabit the surface of the water. There is nothing like using dry flies and watching trout and grayling rise to the surface. To purists dry fly fishing is the true art-form of fly fishing, indeed some rivers only permit dry fly fishing.
After much debate about which natural the Coch-y-Bonddu is meant to represent Mr. A Courtney Williams wrote to a number of Welsh anglers, spread throughout the country, asking them to send him an example of which insect they thought this to be. All the returns he received were of P. Horticola. This beetle is common throughout Scotland and Wales and first appears in strength in early June, sometimes in enormous numbers.
The artificial seems to be a little more generic than a truly accurate P. Horticola and as such gives it a somewhat wider trout-appeal.