SCIENTIFIC NOTES. 9 



The above variety was caught on September 25th, hi a meadow en- 

 closed by a wood, near Agram, where other Colias species occur. It 

 appears to have freshly emerged, and is perfectly developed. — August 

 Onsen, Bakacgasse No. 4, Agram, Croatia. 



fgCIENTIFIC NOTES. 



Variation in the Colour of the Cocoons of Halias chlorana. — I 

 suppose all students of variation have interested themselves in that 

 particular phase of the subject in which certain larvae appear to have 

 a remaikable foresight, and, according to what their surroundings are or 

 have to be, appear to have a tendency to spin a cocoon of the colour 

 which will protect them best from their numerous enemies. The 

 cocoons of Eriogaster lanestris and Saturnia carpifii are those which 

 have been more generally used for experiment by Mr. Poulton, and 

 others who Ixave followed in his footsteps, and it struck me when at 

 Deal in August, collecting larvae of Halias chlorana^ that it would be 

 equally easy to experiment with this species, and far more easy to rear, 

 so that there might be no deaths etc., to modify the success of the 

 experin)ent. I collected some 600 larvae, and put them with a quantity 

 of their foodplant into large linen bags of three different colours, — (i) 

 dark slaty black, (2) white, (3) a bag which had once been white but 

 was now very dirty. In about three or four days, some larvje in each 

 began to spin their cocoons on the sides of the bag, and, much to 

 my astonishment, there certainly was an appreciable difference in the 

 colouring of the three lots, especially in the bags numbered i and 2. 

 Those in bag i were, with two solitary exceptions (and these were 

 normal), out of just above 20 cocoons, of a somewhat reddish colour, 

 those in bag 2, were of a rather pale straw colour tending to white, with 

 the exception of three that were normal, those in bag 3 were nearly all 

 normal, but there were 2 dark reddish cocoons and two very pale ones 

 mixed up with the normal ones. I at once assumed that, in a state of 

 nature, hereditary influence would be strong enough to produce occa- 

 sionally paler cocoons than the type, and vice versa, although the greater 

 number of the cocoons would be of the dull greyish ochreous tint which 

 appears to be normal. To satisfy myself as to this, I accordingly 

 sleeved some out, and the result obtained so far justified my expectation 

 that I got cocoons of a decidedly darker, and others of a decidedly 

 paler tint than the great majority of these, proving that, even in nature, 

 there is some tendency to variation, and I came to the conclusion that 

 those in the dirty bag (3) were spinning up more according to the normal 

 condition of things in nature, and that the few specimens in bags i 

 and 2, which varied so greatly from the general body in those bags, 

 varied simply from an inherent tendency in the species to vary in spite 

 of the surroundings, and that the others, having adapted themselves to 

 their surroundings, had spun darker cocoons than usual in bag i, and 

 paler in bag 2. Thus far, then, my observations had led me to believe 

 that this particular species could adapt itself within certain limits to its 

 surroundings, and that the theories put forward in this direction were, 

 in the main, correct. 



1 then began experimenting further. Each larva, when full-fed, 



C 



