116 THE CANADIAN ENTOMOLOGIST. 



It will be seen that in the ornamentation of the dorsal region the 

 two forms differ materially. 



Of greater importance is the fact that while the larvae that in 1901 

 produced residua had " a small, ill-defined black blotch at corners of 

 mouth," those that in 1903 gave ohscura had "a black acuminate dash, 

 extending from the mouth two-thirds of the way to top of head." 



These descriptions were taken from several larvre in both instances, 

 and the differences here recorded would indicate that the two forms 

 should be classed as distinct species. 



Colour variations in Catocala larvae are frequent, and have no 

 connection with the variations of the imago. But the pattern of the 

 dorsum and the black marks of the cheeks are constant, and are good 

 specific characters. 



Described as a distinct species, the catalogue makers, with no better 

 guide than a comparison of cabinet specimens, listed r^j/V/z^rt as var. "a" 

 of obscura, thus assuming a knowledge that they did not possess, and 

 thereby misleading all who were depending upon such lists for aid in 

 arranging their collections. 



Prof. Smith states in the preface to his new Check List that " all 

 species and genera are treated as presumably good, unless i/ie contrary 

 has been established.^' But residua is still var. " a " of ohscura in his 

 list. It would be interesting to learn who established the identity of these 

 two forms, and just how it was done. 



Catocala Whitneyi furnishes another case in point. 



Soon after its description it was denied specific value, and became 

 var. "a" of abbreviatella. It so appears in Smith's List, both the old 

 and new editions. 



This error is also given especial prominence in the " Moth Book," 

 where the two forms are shown side by side. 



Their likeness, together with the author's expressed opinion that they 

 are forms of one species, will undoubtedly be taken as proof indisputable 

 of their identity by the majority of readers, 



kx. our former home in Nebraska we used to take a it\\ abbreviatella 

 every year. We noted that they invariably began to appear from one 

 week to two weeks earlier than Whitneyi. When the latter was fresh 

 and coming to bait nightly in considerable numbers, specimens of the 

 former in a more or less worn and faded condition were to be encountered. 



