The YOtfHG HATtfBAMST: 



A Monthly Magazine of Natural History. 



Part 86. FEBRUARY, 1887. Vol. 8. 



FIELD-WORK FOR LONDON LEPIDOPTERISTS 

 IN FEBRUARY AND MARCH. 



By ERNEST ANDERSON. 



TOWARDS the end of the present month, the lepidopterist may fairly ex. 

 pect to commence active field-work, and this renewal of old habits and 

 associations is always most enjoyable after the dull monotony of the winter 

 months, when very little can be done, except indoor work, such as arranging 

 and classifying our captures of the previous season. 



For London lepidopterists, Richmond Park is generally considered the 

 most convenient and productive collecting ground at this time of the year. 

 In the first place it is the head-quarters in our district of Nyssia Aispidaria, 

 a species which maintains its reputation of being very difficult to secure in 

 consequence of its uncertain appearance, many lepidopterists having searched 

 in vain for it, season after season. It varies in its time of appearance from 

 the middle of February to the middle of March, though rarely being so late 

 as the latter date. Judging from the observations made, this species must 

 emerge as it were in a body, that is, almost the whole generation leave the 

 pupal state simultaneously, say in a period extending over about three days. 

 It is owing to this fact that the insect is so hard to procure, as by missing these 

 three or four particular days all chance of obtaining it is gone, as they rarely 

 settle on the trunks again after having once flown, but prefer the large 

 boughs of the oaks, which are, of course, inaccessible to the entomologist. 

 Should the visitor, however, be fortunate enough to hit upon the exact period 

 of their emergence, he will have no difficulty in observing the males of this 

 very interesting species, as they are drying themselves on the lower boles of 

 the large oak trees. The female which is apterous, is far more rarely seen, 

 and is only to be obtained by very careful examination of the clefts and crevi- 

 ces of the bark. Most of our leading Loudon lepidopterists visit the locality 



