W. H. HARRIS ON THE DENTITION OF THE DIPTERA. 397 



far as my researches have been carried, the dental organs of flies 

 appear to supply a fairly constant additional set of specific 

 characters. Among the vertebrates these organs are certainly 

 regarded as characteristic. I therefore see no reason why the 

 Diptera should be excluded ; but much has yet to be done before 

 this question can be satisfactorily answered. 



In a monograph by the late Dr. R. H. Meade, of Bradford, 

 on the British species of the Flesh-fly, Sarcophaga, published in 

 the Entomologist^ s Monthly Magazine, February, 1876, page 21 7^ 

 he remarks as follows : "The majority of these flies are so much 

 alike, that it is impossible to distinguish the separate species 

 from each other by mere differences of colour and design ; and 

 the greater number of authors having chiefly relied upon these 

 points, very few of the species described by them can be 

 determined with certainty." 



It was my privilege to have the advantage of this gentleman's 

 experience in the matter of identification, he having become 

 interested in the subject I was engaged with; and in a letter I 

 received from him he made the suggestion that investigation as 

 to the value of the teeth as reliable specific characters would 

 probably prove valuable. His lamented death has been an 

 irreparable loss to me, and has so far prevented any progress 

 in this direction. It is almost superfluous to remark that 

 assistance in this particular portion of the subject would be 

 welcomed, for the labour of many hours could often be dispensed 

 with if specimens could be submitted to an expert for specific 

 determination. 



Note. — In the discussion which followed the reading of the 

 above paper, the question was raised by one of the members 

 whether these organs could really be called teeth. Without 

 wishing to enter into a discussion on this point, I may refer 

 those who may still have any doubt upon the matter to the 

 monograph on the Blow-fly, by Dr. Lowne, in which the simple, 

 strap-like organs of that insect are by him denominated teeth. 



What is a tooth ? Referring to " Cassell's Encyclopaedic 

 Dictionary," vol. vii., page 128, under the word "tooth," the 

 following definition is given : " Any projection resembling or 

 corresponding to the teeth of an animal in shape, position, or 

 office. A small narrow projecting piece, usually one of a set." 



