MR. P. H. GRIMSHAW has recently published a useful article entitled “Introduction to the Study of Diptera, with a Key for the Identification of Families” (Proc. Roy. Phys. Soc., Edin., 22, Pt. 4, July 1934). The paper gives a clear account, accompanied by illustrations, of the various structural features of importance in classification. A list of the chief general works on the order is provided and a diagnostic key to all the existing families. The key is translated and adapted from Lindner's “Fliegen der palaeartischen Region” and should prove especially valuable to those entomologists who are not specialists in the insect order concerned.