1 46 [June, 



somewhat less confidence we can treat as probably distinct (<x) forms 

 with black tegulse, or sterna, or pleurae, etc. ; and (b) forms where the 

 parts in question are white or brightly yellow. Even in cases where 

 we feel instinctively that a character must be somewhat variable (e.g., 

 the appearance of pictura in the shape of two small flecks on the 

 mesonotum, or of a yellow margin at the apex of the propodeum), its 

 presence will often suggest to us a possible determination of the 

 specimen under examination, though we should be cautious in drawing 

 inferences from its absence. Personally, though I cannot think it 

 proved, I think it more than probable that some, if not all, of these 

 characters are of real " specific " value ; and that, at any rate, we have 

 at present no other characters at once as easy and as likely to be 

 reliable, as the presence or absence of pictura albida vel flava in 

 particular portions of the integument. 



Characters which are apparently fairly constant, but exceedingly 

 " critical," and liable to be seen by the inexperienced where they are 

 really non-existent, have been pointed out in the comparative turgidity 

 of the tempnra (" Head narrowed or otherwise behind the eyes ") ; the 

 exact dimensions and sculpture of the vertical area , the comparative 

 lengths of calcaria and metatarsi, etc., etc. Observations of such 

 characters made in haste, or in poor light, or without care to " pose " 

 the objects to be compared in the proper situation, are worse than 

 useless. And I have learned absolutely to distrust measurements of 

 such small objects made by the eye simply. If they have to be made, 

 they should be made with a proper micrometer, and at such magnifica- 

 tion that if the object is not exactly level, it cannot be sufficiently in 

 focus to be measurable at all ! 



May I venture to ask that anyone using my Tables shall take 

 not too literally every such unqualified expression as : entire, simple, 

 interstitial, immaculate, equal, all over, etc., etc. ? Allowance must be 

 made for the impossibility of making general statements without a 

 certain amount of inexactitude, and also for the fact that probably no 

 " character "is altogether invariable. 



I have only to add, before commencing my Tabulation that, after 

 correspondence with Dr. Enslin on the subject, I am now convinced 

 that the black-faced Tenthredopsis with white-ringed antennae, which 

 Cameron identified with gynandromorpha, Eudow— a very mysterious 

 " species," and probably not a Tenthredopsis at all — may safely be 

 struck out of our List. It is doubtless T. andrei, Knw., a species 

 confined to the eastern part of the Mediterranean (Greece, Corfu, etc.) 



