274 



THE ENTOMOLOGIST. 



LIGHT TRAP EXPERIMENTS IN CONNECTION WITH 

 TEMPERATURE, ETC. 



By Major Frederick Gillett. 



In Whitaker's Almanac will be found the amount of light and 

 darkness each night given in the form of a rectangle divided into 

 four equal squares, each square representing one quarter (3 hours) 

 of the period from 6 p.m. to 6 a.m., the shaded squares being 

 darkness, when there is no light from the sun or moon. These 

 data have been accepted in the following tables. The temperatures 

 which I give are the shade temperatures at 8 a.m. The trap has 

 been run from 10 p.m. to 3 a.m. (summer time when that is used), 

 the electric light being cut off automatically by an alarm clock, but 

 I did not begin to run it consecutively till the beginning of May, 

 since which date, however, I ran it regardless of weather whenever 

 I was at home. The numbers of moths are given regardless of 

 species, although it is curious that on certain nights a particular 

 class of moths may be attracted. For instance, one night there 

 may be several species of Prominents, whereas the next night there 

 may be none, but instead, perhaps, Poplar and Eyed Hawks. 



A dark, warm, thundery night with a drizzle of rain will nearly 

 always bring a large number of moths to the trap, although one 

 is quite as likely to obtain something good when very few captures 

 are made. My impression is that a dark night is better than one 

 with a bright moon, but at the same time I do not consider it an 

 invariable rule. Temperature does not appear to have much 

 effect, except when it drops very low. Males come to light far 

 more freely than females ; at the same time a very fair sprinkling 

 of females will be found amongst the captures, and I have even 

 had batches of eggs laid in the trap during the night. 



Date. 



Temperature, 

 8 a.m. 



No. of 

 moths. 



Bemarks . 



April 9th 



36° 



Ml 



Light all night. 



„ 29th 



44° 



6 



Dark 9 p.m. to 6 a.m. 



„ 30th 



42° 



6 



,, 12 a.m. to 3 a.m.. 



Mav 2nd 



44° 



4 



\ 



,/ 4th 



46° 



4 



' >> )> |! 



„ 5th 



44° 



1 



Light all night. 



„ 6th 



47° 



1 



„ 7th 



50° 



1 





„ 8th 



60° 



5 



) » > i 



„ 9th 



60° 



2 



" 



„ 10th 



50° 



4 



M )) 



„ 11th 



44" 



Nil 



' » tt 



„ 14th 



49° 



1 



Dark 9 p.m. to 12 a.m. 



„ 15th 



50° 



2 



„ 20th 



56° 



4 



,, 9 p.m. to 3 a.m. 



