1882. J 237 



But, suppose we were all agreed, on the score of the universal brotherhood of 

 science, to be reformed, become decimal-doctrinaires, and give up for the future the 

 use of one measure for the other, what is to be said about the old and young brethren 

 ot all countries who have already described thousands of insects with the old ortho- 

 dox style of measurement, and the trouble they have given to their successors if 

 their " lines " are to be converted into millimetres ? Could they not well ask — " To 

 what end will you do this, considering you understand perfectly well what is intended, 

 and what will you have gained when you have done it ?" Truly, this suggestion of 

 the use of smaller measurements seems to be founded on the fallacy above mentioned, 

 and the moderns who have introduced and would enforce the Procrustean standard 

 of millimetres, to the exclusion of lines, are really the authors of needless trouble, 

 and have much to answer for. But if it is now too late to revert to the inch and 

 line exclusively, and it is desirable to meet objectors, the equivalent to the old 

 measure, whatever it may be that shall be employed, could be added in millimetres, 

 like the different thermometrical readings of Fahrenheit, Reaumur, or Centigrade, 

 which, for those who may be concerned, are often put in conjunction. 



It only remains to notice what pertains to the measurement of parts of insects, 

 and to say that such is rare y given in figures, or if so given, is of much value ; a 

 comparative statement of relative proportion being far better, because such propor- 

 tion is at once recognisable by the eye, without reference to any detached scale. 



Mr. McLachlan's suggestion must be understood as his own personal proposal, 

 and my dissent must also be considered my own individually, like the expression of 

 the opinion of any other contributors ; neither being in any way put forth editorially. 

 ■ — J. W. Douglas, 8, Beaufort Gardens. Lewisham : February 1st, 1882. 



Measurements in descriptive Entomology. — Owing to severe family bereavement, 

 my friend and colleague, Mr. Douglas, had no opportunity of seeing what I had 

 written until it was on the eve of publication. This was unfortunate, because it 

 prevented me from knowing that any British Entomologist was in the habit of using 

 the " Paris inch " as his standard. I now find that at least two have been so doing. 

 My friend's counter-suggestion is that the Paris inch should be our standard, to the 

 exclusion of the English inch and the metrical (a better term than " decimal ") 

 system. No doubt the Paris inch was in common (not universal) use outside this 

 country. Outside this country it is now commonly (but not yet universally) aban- 

 doned by all nations in favour of the metrical system, which is the generally accepted 

 " standard," an end at which my suggestion was aimed. The now venerable Bur- 

 meister, who, in 1832 (English translation, 1836) when a young man of 25, wrote 

 that " the Paris line has been adopted as unit," has now, at the age of 75, so far 

 conformed to general usage, that in his works on the insects of the Argentine Re- 

 public, he places the metrical equivalents in brackets after the dimensions according 

 to the Paris inch. This latter has never been in general use in this country, and I 

 hardly expect it will now find favour as a standard with us, after having been pretty 

 generally abandoned abroad. It appears to me much to be preferred that those 

 British Entomologists who object to the millimetre should continue to use (as most 

 of them did use) the English inch ; it is familiar to all " Britishers " (though not 

 always so to our foreign brethren), and it is not good that there should be two mea- 



Isurements in use with us bearing the same name but not equivalent in value. For 

 my part, I have not the slightest uneasiness as to our ever adopting an almost obsolete 



