70 



THE NATURE BOOK 



louslv their life schemes are harmonised 

 with the seasons and the particular food 

 and conditions they will need ; indeed, 

 the dry-as-dust collector knows scarcely 

 anything of these things, his chief know- 

 ledge consisting of dates and districts 

 when and where the insects may be 

 found. 



Let me, therefore, warn the would-be 



CATERPILLARS OF BRIMSTONE BUTTERFLY. 



Nature student not to be too anxious to 

 collect. He will be able to do this, if 

 he so desires, later on, when Jie has learnt 

 something of the ways and habits of the 

 insects, and much more efficiently then, 

 since his observations will have guided 

 him and given him method in his work. 

 How then must the amateur begin ? 

 For answer let us consider the case of the 

 Brimstone Butterfly. 



In early May we observed that the 

 butterflies were love-making, and after 

 the mating attention is given to family 

 matters, which, in the case of insects, 

 usually means merely the depositing of 

 eggs in suitable situations for the inde- 

 pendent development of the offspring. 

 When digging in the garden early in the 

 year we may come upon an instance of 

 e.xceptional care for the young of insects. 

 I refer to the common Earwig, which 



maternally sits upon her batch of forty 

 or fifty eggs until they are hatched, and 

 even thereafter guards and protects her 

 young. The Brimstone Butterfly, how- 

 ever, rarely lives to see her offspring, 

 although her eggs hatch into caterpillars 

 in some eight or nine days after they are 

 laid, and even if she should live it is 

 improbable that she would ever recog- 

 nise them. All 

 interest in her 

 offspring ceases as 

 soon as she has 

 deposited the last 

 of her eggs ; by 

 that time, too, 

 her strength is 

 so completely ex- 

 hausted that, it 

 may be, she has 

 but a few hours 

 to live. 



Since this but- 

 terfly deposits her 

 eggs only on the 

 two British spe- 

 cies of buckthorn 

 shrubs, they are 

 easy to find. 

 They are usually 

 placed on the 

 veins of the un- 

 der sides of the 

 leaves. I need 

 not introduce a 

 picture of the egg, because it is almost 

 of the same form as that of the Orange- 

 Tip Butterfly shown in mv previous 

 article (p. 47), being only a little more 

 elongated. So when the pale yellow but- 

 terfly is seen fluttering about amongst 

 the leaves of buckthorn shrubs, there is 

 the first observation to record. 



Eight or nine days after her visit some 

 little cater]:)illars emerge from the eggs 

 which she has so diligently placed amongst 

 the leaves. About four weeks later you 

 may go and shake them from the trees, for 

 they are then full-grown. In the illustra- 

 tion on this page the caterpillars are shown 

 feeding ; they are coloured pale green with 

 a white stri})e along each side of their 

 bodies. This, then, is the reason why early 

 in June Brimstone Butterflies are not to be 

 seen ; only an occasional belated examj)le, 

 or a very early one of the next generation, 



