1880.] Correspondence . 407 
negro cross. He married also a woman unconnected by blood ; 
the marriage is unfruitful. 
The latter case is interesting as showing the issue of three 
generations through pure white mothers* The first family are 
not so robust as the second family : this probably is due to the 
intermarrying with women of the same stock. — I am, &c., 
S. B. 
THE WILD BIRDS’ PROTECTION ACT. 
To the Editor of the Journal of Science. 
Sir, — Your statements concerning the failure of this Adi are, I 
believe, corredl ; but the reason is apparently because the penalty 
inflidled, in the few cases which have been brought before the 
magistrate, is too low to be of any effedl. A fine of half-a-crown 
will never prevent such offences. Moreover, it is rumoured that 
the men who adlually ensnare birds are merely the servants of 
dealers, who agree to hold them harmless in case of a penalty. 
The Adi requires sharpening in several respedls. I do not, how- 
ever, think that you need expedl the Society for the Prevention 
of Cruelty to Animals to take adlion. — I am, &c., 
H. T., of B. 
FROST AS A VERMIN-DESTROYER. 
[To the Editor of the Journal of Science. 
Sir, — Well-meaning people sometimes tell us that severe win- 
ters are very serviceable, by destroying noxious insedts. Such, 
however, is not the evidence of fadls. The prolonged and 
deadly cold of the winter of 1878-79 has not prevented the 
ravages of certain caterpillars from being unusually extensive. 
Abraxas grossulariata and Plusia gamma were exceptionally 
plentiful, in every stage of their existence, during the quasi- 
summer. The last winter, again, was much more severe than 
ordinary, but it has again proved utterly unavailing against the 
former of these two species, which is literally swarming. — I 
am, &c., 
An Old Naturalist. 
