Cite the scanned version of the original dicionary like this:
Toller, T. Northcote, and Joseph Bosworth. "gærs-hoppa." An Anglo-Saxon Dictionary: Based on the Manuscript Collections of the Late Joseph Bosworth : Supplement. Oxford: Clarendon Press, 1921. 278.
, an; m. A grass-hopper, locust; lŏcusta, cĭcāda :-- He cwæþ and com gærshoppa dixit et vēnit lŏcusta, Ps. Lamb. 104, 34 : 108, 23. Cwómón gærshoppan grass-hoppers came, Ps. Th. 104, 30 : 77, 46. [Orm. gress hoppe locusts.]