NOTES ON THE AGROTlDiE. 189 



A. nigricans swarm it is, I know, impossible to find a specimen 

 of A. tritici. Besides this, A. nigricans, except in ground colour, 

 is so constant in markings that it required no confirmation to 

 convince me of their actual distinctness. In cases where 

 A. nigricans is mentioned as a probable form of A. tritici, I have 

 doubts whether the forms obtained and called nigricans are 

 really the same species we know by that name. I had no idea 

 that anyone wished to prove that A. segetum and A. tritici are 

 the same species; and the life-history of A. segetum is, I believe, 

 fairly well known. With the latter part of Mr. Gardner's note I 

 can quite agree ; and I think he points out the exact spot where 

 the weakness of many old records exist, viz., in assuming that a 

 large number of larvse obtained in a place at the same time must 

 of necessity be one species, and all insects bred from such larvre 

 must be forms of the same species. 



I was also very pleased to see Mr. Gregson's letter taking up 

 the other side of the question, viz., the reason for considering 

 A. tritici, A. aquilina, and A. ohelisca specifically distinct. His 

 letter is instructive, so far as it goes, but it proves nothing. In 

 the first place Mr. Gregson makes a point of the difi'erent size of 

 the larvae. I have some specimens of undoubted tritici much 

 larger than any aquilina or ohelisca I have ever seen. Everyone 

 knows that species vary in size. Is it probable that the larva 

 which will produce a small specimen shall be the same size as one 

 that will produce a large one ? The Ij inch and Ig- inch test, 

 therefore, will scarcely apply. Everyone who breeds Noctu£e of 

 the Agrotis type must have noticed that we want something very 

 much more definite than distinctness of markings and intensity 

 of colour in determining similar larvae. "^. tritici has the ends 

 reduced." ''A. aquilina is slightly reduced at second and last 

 segments." These I suppose are the "ends." Hence I see no 

 distinction here. In fact, until they are bred from eggs and not 

 from captured larva3, and until it has been proved that it is 

 impossible to breed A. aquilina or A. ohelisca from tritici eggs, 

 and vice versa, I maintain that we have no right to confuse the 

 younger entomologists or disgust ihe older. New species are not 

 so important as entomological science, and doubtful species had 

 better be left alone, as far as lists and names are concerned, 

 until they are no longer doubtful. With all due respect to 

 Mr. Gregson's experience, I maintain that the illustrations of 



