92 THE CANADIAN ENTOMOLOGIST. 



The frenulum. 



The tibial spurs. 



The hair pencil on hind tibice of male. Dr. Hulst used this as a 

 reliable factor, and my experience fully warrants the value he placed 

 upon it. 



Auxiliary Group. 



The characters here classed are not to be wholly relied upon. Many 

 of them will be used as useful aids, but will be omitted where found too 

 uiistiible. 



'The tufts of thorax, abdomen, and patagia, chiefly because of their 

 liability to removal by abrasion. The same might seem applicable to the 

 hair pencil, but in only one genus (Epimecis) have I had ai^v ditlficalty 

 with it. 



Venation (except veins 5 and 8 of hind wings). 



The foveal gland beneath tvings. In some EnnominjB it is well 

 developed, in others difficult of detection, or absent, and thus falls without 

 the ])ale of fixed characters, but is useful in defining certain genera. 



The accessory cell. The extensive use which has been made of the 

 accessory cell by Dr. Hulst in the separation of Geometrid genera, fol- 

 lowing the assertion of Mr. Meyrick that it was an invariable structure, 

 seems not to be warranted, at least so far as the American fauna is 

 concerned. Selecting spedies in which I have considerable material, I 

 give the result of an investigation, which it was not necessary to extend 

 because here is enough evidence to effectually debar its future use. Of 

 Cladara atroliturata, Walk., which, according to Hulst, should have two 

 acc'y cells, out of 58 examples tested, 56 were normal and ttvo had only 

 one cell. O'i Nyctobia limitaria, Walk., 15S examples divided as follows: 

 28 had one cell, 21 had one cell in one wing and two in the other, while 

 109 were normal. Of TepJiroclystia latipennis, Hulst, with one acc'y 

 cell, 16 examples separated thus: 9 with one cell, 7 with two cells. 

 Here the anomaly is shown, viz.: 9 specimens with one cell would go 

 into the geiius Tephroclystia, while the other 7 of the same species would 

 fall into Eucymatoge, an impossible situation, hence I have abandoned 

 its use almost entirely, and by so doing it becomes imperative that there 

 be a rearrangement of the genera and species of Hydriomeninae. 



(To be continued.) 



