Clje Cciuciiiian Jlntomalajbt, 



Vol. XLIV. 



LONDON, AUGUST, 1912. 



No. 8 



GEOMETRID NOTES. 



REyrsiON of the Genus Hydkiomena Hub. Group with 

 Moderate Palpi. 



BY L. W, SWETT, boston, MASS. 



8. Hydriomena autumnalis Strom (Det. Kgi. Danske Vid. Skrift. 

 Selsk., p. 85, 1783). Palpi moderate. 



We have generally regarded as typical aidiimnalis a grayish form 

 with clear mesial space and slate-coloured bands, bordered with olive. It 

 occurs in June and July in both Europe and America, but there is a May 

 brood which we do not commonly get here. We imagine our species to be 

 the same as the one that is found in Europe, but do we really know the 

 form that Strom described as autumnalis ? It seems strange that a 

 geometrid^^ccurring only in the eaily summer should be called autumnalis. 

 This same doubt seen ed to arise in the mind of a German specialist, for 

 Hoyningen-Heune, in the Berl. Eut. Zeit., Vol. 51, p. 254, 1906, discusses 

 this question, and pleads for the name trifasciata Bockhausen for this form. 

 He claims it answers Bockhausen's description better than Strom's, which 

 seemed to him to apply to some unknown or unrecognizable species, 

 possibly Larentia autumnalis Bockhausen. Perhaps he is correct, but 

 it would be hard to prove, as Strom might have called it ajituninalls from 

 his having found the larvae in the fall or for various other reasons. Since 

 nearly every collector recognizes it by the older name, autujnnalis, and 

 it is difficult to prove otherwise, I think it better to retain this name. The 

 form found in America is very close to the European in colour and mark- 

 ings, but there are slight differences which, should the genitalia prove 

 different, would refer it to pluviata Guenee (Phal, II, p. 378, No. 1505, 

 1857)- Guenee states that the American form has more pointed fore 

 wings, the lines are not so close together, and those bordering the mesial 

 band are more obh'que and that ihe median space is larger. He mentions 

 having a specimen with the mesial space shaded with pink, and to this 



