198 THE ENTOMOLOGIST. 



VARIATION OB' CERTAIN AGROTID^. 



By J. W. TuTT, F.E.S. 



(Concluded from p. 176.) 



Now with regard to cursoria. A well- developed local form of 

 this " non pale-costa " part of the group is obtainable on many 

 parts of the coast, which seems at first sight sufficiently distinct 

 to call a species ; but this form is in itself very inconstant. It 

 is distinct in itself, but has a great number of local races and 

 forms ; and since our correspondents send us picked insects 

 which they themselves are able to distinguish as belonging to cur- 

 soria and not to the allied tritici, it is difficult to say how reliable 

 the forms are, or whether, if one obtained an immense series of 

 tritici and cursoria from the same districts, they would exhibit the 

 same distinctness they certainly appear to do. To return, the 

 Lancashire specimens have generally, in the " non pale-costa " 

 type, a well-developed dark mark in the lower half of the reniform. 

 This seems to be there a most constant character, but I have tritici 

 from Deal with this same character well developed, and some 

 undoubted cursoria forms are without it. From Sligo, wliere my 

 kind friend Mr. Percy Kuss gets cursoria perhaps more abun- 

 dantly than any other collector, I have a long series, but no trace 

 of this special development except in two specimens, and then 

 only slightly ; neither does there appear to be this development 

 among the cursoria from the Welsh coast. On the Scotch coast 

 some marvellous specimens are obtainable, characteristic ochreous 

 cursoria leading up to perfectly melanic forms. To me a very 

 strange and important problem presents itself: Why is it that in 

 all these localities none of the magnificent forms — white, slate- 

 colour, black cursoria-\\ke forms — of tritici are present? lam 

 assured by collectors from these localities, that the great mass of 

 variation of the forms without pale costse that I get at Deal is 

 not obtainable in their localities ; and when Mr. Percy Russ 

 looked over my collection a few weeks ago, with all his experience 

 he said he had never met with such forms, and I think he gave 

 up altogether the attempt to solve the problem which species 

 many of my specimens represented. But now comes another 

 important matter. Cursoria is looked upon as an insect without 

 a pale costa, but I have seen some splendid varieties from Sligo, 



