MELANIC VARIATION IN LEPIDOPTERA. 87 



male of Colias cdusa, a pair of Satyrus titlionus, a pair of Thecla quercus, 

 and three specimens of Lithosia straviineola. A thermometer lying on the 

 grass by the side of the snow stood at 48° Fahr. At noon Cha!ro2)hyllata 

 already showed decided signs of melting the snow, so did Satyrus and the 

 female Thecla ; the black edge of Colias, which did not lie very flat upon 

 the surface, had also made a slight impression ; the others had made none. 

 At 12.30 the same three continued to increase their impression ; the others 

 still made none. 



" I then placed a piece of black and a piece of white cloth in the same 

 position. At 1 p.m. the mercury stood at 52°, and the effect produced by 

 the darker insects was still more decided. But although the pale ones 

 remained upon the surface they did not appear to protect the underlying 

 snow from the heat-rays to the same degree as did the white cloth, 

 which remained on a slight eminence as the sun thawed the snow around 

 it. The nearest approach to this protection was evidently accorded 

 by the white Acidalia immutata. At 1.30 Charophyllata and the black 

 cloth continued to sink, and the male of Thecla quercus was apparently 

 giving off as much heat below it as the female, but not being set with the 

 wings equally flat had not shown the effect so soon. The Lithosia had by 

 this time also had a very slight effect upon the snow, but not so much 

 as any of the darker insects, and ChcETophyllata had decidedly won the 

 downward race among them." 



The address consists of twenty-eight pages, and is replete 

 with interest and instruction. Tliere are many collateral points 

 adverted to, — among them that in the Lepidoptera, as stated in 

 the fourth quotation, there is less disposition to vary in the 

 female sex. This is quite in accordance with what may he 

 observed in cases where the female retains the normal coloration 

 of a group, and the male departs widely from it — e. g., Spilosovia 

 mendica, Ocnerla dis'par, G7iophria quadra, and others. 



The address of Lord Walsingham is a most valuable addition 

 to philosophical entomological literature. It will incite the young 

 to a higher class of Natural History studies, and is full of in- 

 formation to those older naturalists who have long pursued this 

 delightful branch of Science. 



J. Jenner Weir. 



