294 THE ENTOMOLOGIST. 



of another 1 in 1500 (which are, I think it must be admitted, high 

 estimates, considering the number of insects annually examined), then 

 the probability of the simultaneous occurrence of two such variations 

 would be 1 in 1,500,000, or, to put it in another way, out of every 2499 

 individuals which exhibit variation there should be only one in which 

 the two variations are correlated. If data of this sort were obtainable in 

 any cases of variation, the extent to which the one variation depended 

 on the other would be proportional to the amount of deviation from 

 the result obtained by supposing complete absence of any such 

 dependence. I should be glad to hear if any of your readers have 

 tried this plan, or if they consider it a practicable means of setthng 

 such interesting points as correlation of variation, supposing it is 

 possible to examine a sufficient number of specimens. — F. P. Bedford ; 

 Sept. IBth, 1894. 



[I am obliged to Mr. Bedford for reminding me of an important 

 omission in my short description of this remarkable insect. I should 

 have mentioned that it had only four legs, as shown in the figure, and 

 these, Mr. Frohawk informs me, are accurately drawn as regards size, 

 shape, and position. — E. S.] 



Note on Smerinthus populi. — I have set thirty-six specimens of 

 S. populi bred from larva3 found here last summer ; a few others came 

 out, but were damaged or dwarfed, and I took no note of sex or colour, 

 but they were not remarkable in any way. Of the thirty-six I now 

 have thirteen are males and twenty-three females ; none of the males 

 are of the red form, and only one tending to a reddish purple ; of the 

 females, five are of the very light red form, seven of the ordinaryred form, 

 and the balance (eleven) same colour as males. — W. B. TnoRNmLL ; 

 Castle Cosey, Castle Bellingham, August 19th, 1894. 



LARViE ON Monkshood. — With reference to Dr. Knaggs' remarks 

 {a7ite, p. 268) on larvffi feeding on Aconitum, I may mention that four 

 years ago I examined this plant for larvffl of Plusia moneta, which, 

 however, I did not obtain ; but I found larvae of Phlof/ojihora meticulosa, 

 and other common species, the names of which I cannot at this moment 

 recollect.— W. M. Christy; Watergate, Emsworth, Hants. 



Note on Naphthaline. — I should like to draw attention to the fact 

 that naphthaline apparently will keep Lepidoptera relaxed for some 

 days. Two of us on board this ship had been out insect-hunting at 

 Mombasa (close to the equator), and had brought back a considerable 

 number of specimens, which, owing to the ship being infested with 

 small red ants, we could only set in detachments, as neither of us had 

 a proper box for stowing setting-boards. On removing some of the 

 insects from the collecting-box (which was quite dry), four days after 

 capture, we found them perfectly relaxed, and fit for setting with the 

 greatest ease. This condition of the insects would appear to be only 

 due to naphthaline, as the atmosphere during the four days had not 

 been at all damp. Previous to this occasion I had not found it neces- 

 sary to put any of the preservative in my collecting-box, as I generally 

 set insects within three hours of capture, but the enormous number of 

 red ants now on board the ship compelled me to do so for safety's sake. 

 I shall be very glad to know whether this property of naphthaline is a 



