244 THE ENTOMOLOGIST. 



environment" fail at Chester, just as they do at other places 

 that could be mentioned. Not only did A. betularia occur as 

 extreme forms this season, bnt a good number of intermediates 

 were taken as well. A few of these are exactly half-way in 

 coloration between the type and var. doubledayaria ; but the 

 chief colour disturbance is a substitution of white, in the latter, 

 in the costal region of the lower wings. In a few specimens the 

 white basal spot of the upper wings is absent. One of the best 

 intermediate forms I have seen, if not the best, of A. betularia, 

 has the following history : — A friend was just about to cover 

 it with his net, as it rested on the ground, when one of the 

 madding crowd picked it up with his finger and thumb and politely 

 presented it, leaving, of course, his monogram upon the insect. 

 Like the preceding species, A. betularia seems to be electrified 

 by the lights, wheeling round in small circles, and finally resting 

 upon the ground, where, unlike the others, it usually rests for 

 an indefinite period. Cats are the greatest enemies to moths 

 when on the ground, for they watch for them through all the 

 hours of the night, and devour them greedily. I have often 

 seen as many as three round a lamp, and they were very 

 unwilling to be driven away. 



Other moths in May were D. vinula, Spilosoma lubricipeda, 

 S. menthastri (sad nuisances, as they occurred in such numbers), 

 Habrostola triplasia, Hadena oleracea (another nuisance), Cara- 

 drina blanda, Selenia lunaria, Odontopera bidentata, Melanippe 

 fluctuate, Pionea forficalis, &c. 



June. 



Acronycta alni. — This moth turned up on the 6th, and 

 occurred commonly until about the 20th. During the night of 

 the 17th I was with a collector who took three. Some of the 

 forms have the upper wings exceptionally dark, almost black, 

 the lower ones appearing in beautiful white contrast, and often 

 margined with a black, suffused border. 



A.psi, A. mec/accphala, A. rumicis. — Common during the first 

 three weeks; A. tridens ('?), possibly, and during the same 

 period ; but I put a query to it as I am unable to distinguish 

 between this species and A. psi. A writer says A. tridens has 

 less than six dashes on the costa ; and A.psi more than six. 

 What the insect would be with six dashes, neither less or more, 

 is not stated. But the ''dashes" are so indistinct that I am 

 unable to determine their number on any given specimen ; in 

 short, I am about as foggy upon the differentiation of the two 

 species as was the hero in Burns' ' Death and Dr. Hornbook ' 

 on the crescent moon : — 



" To count her horns wi' a' nay power I set mysel', 

 But whether she had three or four I couldna tell." 



