SPRING COLLECTING AT LYNDHDRST, 215 



expect we all of iis miss a good many, because they are so exactly the 

 colour. I daresay the light ones are the most like to their gi'eat-great- 

 great grandmothei's. Anyhow it is a great joy to start a theory. Do 

 the light ones sit on the light trees, and the dark ones on the dark 

 trees ? Well ! do they ? No. I think that goes to answer peoj^le 

 who still say that these things make themselves like their surroundings 

 on purpose. But then there are a few miserable beasts, like the 

 chameleon, which can change colour all in a moment, and be green 

 when they are sitting on grass and grey when they are sitting on stones. 

 There are two lines for you to work out. Take your pick, but make 

 some theories when you get the chance. It is very good fun, and may 

 be useful. Have you found as many as you want ? If so let us leave 

 the rest, to make material for more theories. 



What shall we do now ? There are a few male Saturnta carpini 

 flying over the heather — but it is getting hot and they are worn by 

 this time. Also they are going a good deal faster over the heather 

 than you and your trousers will go through it. Better wait and get 

 the larvaj in August or September. If you could bring a bred female 

 here, you'd have the males of the whole country crawling over your 

 hands and arms. How they find you out I can't say ; but they do. 

 I've done it, and they come in crowds from all points of the compass. 

 Nor is the phenomenon confined to this insect or this genus. The 

 peculiarity is that all this genus, except one or two, exhibit it, and stray 

 sijecies, here and there, out of other genera. Perhaps it is more 

 genei'al than we imagine. Now that entomologists breed more insects, 

 they are making fresh discoveries. I don't think that the time has 

 come yet for much of a theory, but it may come bxij time, so be on the 

 look out. There is a chance for you ; but you must enter the lists and 

 not just look on. Breed females and put them into a muslin bag and 

 take them out into country where you know the males are, and watch 

 where they come from. Staurojms fagi seem to come down from the 

 tree tops, others rise out of the ground. You'll learn something of 

 their habits at any rate. 



Let's go to that alder-bed and beat for larv^ of Geometra 

 papilionaria. You'd better roll your trousers ujd to your knee, as 

 the country is somewhat moist. Another time bring a joair of canvas 

 shoes to do this sort of work in, and keep your boots dry ; you can 

 leave them at the pub. It's hard work beating alders, with a quaking 

 bog under your feet, and it looks foolish work, as the leaves are only 

 just showing. But the larvae are there, and have been since the 

 autumn. You will have to keejD your eyes open here too. They are a 

 very exact imitation, in their small stages, of the little stumpy red 

 chips of the alder twigs. You will pass some over, even in the beating 

 tray. Later on, as the leaves come out, they take a bright gi-een skin, 

 and they have an intermediate stage, just about now, when they are 

 red, with a gi-een crest along their back, painfully like the leaf just 

 breaking out of its sheath. If you haven't seen them in all their stages 

 you will think that I am talking nonsense, — but wait a bit. When 

 they are full-gx-own, some are green and some are bro^vnish, just like 

 the catkins of the alders and birches, especially the latter, on which 

 also they feed. Upon my word, it looks as if I were colouring and 

 shaping the larv^ to suit the trees, but I really don't think I am : the 

 imitation is so very exact. But theories here are much harder to make. 



