NOTES AND OBSERVATIONS. 17 



examples of var. thomp^oni, were put up in six lots, and brought for 

 the best 47/6, and for the other five from 35/- to 30/- per lot. The 

 long' series of Pieris napi, on which the late Mr. Harrison in con- 

 junction with Mr. H. Main had expended so much time and attention 

 in their experiments in crossing various local forms, were not included 

 in the sale. — R. A. 



Dragonplies bred in 1912. — I have bred this year Gordidegastar 

 anmdaius (one), JEschna cyanea, Libellula quadrimaculata, Ischnura 

 clegans, Agrion puella, Pyrrliosoma nymphida, Erythromma naias. I 

 was able to watch the emergence of an JEschna cyanea, which took 

 place about midnight. I noticed a nymph running up and down a 

 stick in apparently great agitation. This was the prelude to emer- 

 gence. The process, up to the expansion of the wings, took just an 

 hour. Tlie nymph of C. ammlatus I had had in an aquarium over 

 two years. It was, of course, in but an early stage of growth when 

 I took it from Oberwater stream, in the New Forest, last June two 

 years ; but it was not so immature as to suggest that it would remain 

 for more than two years in the nymph stage. The imago finally 

 emerged towards the end of Juno in this year. I did not take its 

 measurements when I first got it, but, roughly, I should say from 

 memory, it was about a quarter grown. How long had it probably 

 been in the nymph stage already ? In all I suppose that stage 

 must have lasted for some two years and a half, seeing that I 

 had it more than twenty-four months. The nymph of this species 

 seems to spend practically its whole life in the mud at the bottom 

 (or in the banks), coming to the surface only occasionally — to 

 change its skin, for instance. But though hidden from view, I have 

 found these nymphs frequently only just below the surface ; being 

 near enough to the top to take a w^orm before it had begun to burrow. 

 They are more deadly accurate in their "shooting" than any others; 

 yet they appear generally to be very sluggish creatures, more so than 

 other nymphs, such as L. quadrimaculata, which also live mainly in 

 the mud ; and in marked contrast to the liveliness of the JEschna 

 nymphs, which go down into the mud only in quite cold weather. 

 This, at least, has been my observation ; I speak, of course, of those 

 I have kept. I am puzzled at the extreme uncertainty of finding 

 nymphs. You may " fish " in streams and ponds where dragonflies 

 swarm every summer and hardly find a nymph ; they will also be 

 plentiful one season and very scarce the next in the same place. 

 There are places, no doubt, where you can practically make certain 

 of some species, such as JEschna cyanea, Libellula quadrimaculata, 

 or, amongst the Zygopterids, Agrion puella. But even these constant 

 habitants vary much in numbers from year to year. Others less 

 common disappear entirely some years. I used to make certain of 

 finding Cordulia cenea in the canal near Byfleet. For two or three 

 seasons I have not seen one there; but I am not there more 

 than two or three times in a year. I may have struck bad days. 

 But nothing in this way surprised (and disappointed) me so much as 

 a nymphing expedition to Wicken Fen in the first week of last May, 

 which produced nothing but one or two of the commonest Zygo- 

 pterids. I wanted especially to get the nymphs of Brachytron 



ENTOM. — JANUARY, 1913. C 



