208 CAPTURE OF NOCTURNAL LEPIDOPTERA. 



I think it may be inferred, from my observations, that 

 insects, generally speaking, are not much under the influence 

 of a backward or forward season in their appearance, but have 

 their regular periods of flight : the great and sudden changes 

 of temperature, combined with the variable state of our atmo- 

 sphere, perhaps, may have some influence in diminishing or 

 increasing the number of insects. Agrotis stiff usa appears at the 

 latter end of September, and continues on the wing during the 

 whole of October; but specimens taken towards the latter end 

 of the month are a good deal faded ; though plentiful this year, 

 they were very scarce the two preceding years. This insect 

 is stated to appear in June, and is supposed to be double- 

 brooded. I only met with one, Agrotis ccqua, a beautiful 

 female, on the 10th of November, 1833. 



I have no doubt that Orthosia litura, Pistacina, and maci- 

 lenta, usually begin to appear at the latter end of September, — 

 as my specimens, captured on the 24th, 26th, and 27th of Sep- 

 tember, 1831, were all as fine as bred specimens; whereas, on 

 the 10th of October, in the two following years, the said 

 insects were more or less faded, and evidently going off. They 

 continue on the wing several weeks. O. Pistacinct is truly 

 denominated a protean species. Out of an immense number, 

 I picked many very singular and astonishing varieties. 



Orthosia lunosa, Agrotis nigricans, Xanthia Jlavago, 

 X. fulvago, citrago, and rajina, also appear at the latter end 

 of September, except the first, which appears earlier. They 

 seem to have a much shorter existence ; for I never met with 

 them in October, except the two latter, which were difficult 

 to recognize, they were in such a wretched plight. 



Orthosia Lota, and O. Jlavilinea, I think I may confidently 

 state, appear about the 10th of October, independent of the 

 variable state of the season, having captured many of the 

 former, and several hundreds of the latter, — " unquestionably/' 

 as Mr. Stephens observes, " a scarce insect near London ;" — 

 they continue, like their congeners, several weeks on the 

 wing ; but not one specimen in ten was worth setting of those 

 which I captured towards the latter end of October and in 

 November. 



Glcea vaccinii, G. spadicea, G. polita, and G. subnigra, 

 begin to appear at the latter end of September, and continue 

 on the wing until the middle of November. I am inclined to 

 think, from a careful examination and comparison of several 



