204 



KNOWLEDGE. 



[September 1, 1897. 



Since Haliday's arrangement of the British MymaridcB, 

 elucidated by Francis Walker, no new species have been 

 recorded, the genera numbering eleven, the species thirty- 

 five, as follows, viz, : — 



Ooctnnus, four species. Mymar, one species. 



Gonatocerus, five species. Cosmoroma , eight species. 

 - Alaptus, two species. Caraphractus, one species. 



LitHS, one species. Anaphes, seven species. 



Evstochtis, one species. Anayrus, four species. 



Camptoptera, one species. 

 Of these I have found representatives of all, and a few 

 notes may not be uninteresting to those who desire to 

 search for these fairy flies. 



O.ictmms. Of this genus I have not found very many 

 specimens. It is thick set, and least like a fairy. 

 Unfortunately Haliday did not publish any detailed account 

 of his captures, but from the fact of his naming one 

 (plentifully represented in his collection) < hctonus licmiptirm, 

 it is just possible it may be parasitic in eggs of bugs. 



Gonatocerus is, perhaps, as plentiful as any in the 

 London district. It is a constant visitor to my garden, 

 though I have failed to discover its nidus. 



Alaptus minimus and fusculu-s have long been known to 

 me. The first-named is not mors than one seventy-second 

 of an inch long, with a sessile abdomen. Its wings are 

 somewhat hatchet shaped, with peculiar enlargements at 

 the base of the inner margin. The lower wings have a 

 crimped appearance, arising from the mackerel marking. 

 This, and in fact all the family, are to be found running up 

 the glass in a greenhouse, especially on the window facing 

 east. Alaptus fusculus is one of the first to appear in spring 

 — its peculiar jerky gait will at once reveal its identity. 

 Of this species I have bred hundreds from the eggs of a 

 psocid (Stenopscocus cruciatus), an insect much like a 

 common aphis, but very active and shy, having a decided 

 objection to being watched. But " all good things come to 

 those who know how to wait,' and wait he must for hours, 

 days, months, and years before the life history of a single 

 sptcies is made out. Haliday mentions that Pohjnema 

 (Cosmocoma) destroys the eggs of the cabbage butterfly. 

 I read this twenty years ago, but I have never yet found 

 one egg " struck." Stenopscocus lays its eggs ou the leaves 

 of various shrubs and trees. I have found them on lime, 

 oak, sycamore, hawthorn, and ivy. They are laid in 

 patches of ten to twenty, the female psocid carefully 

 weaving a silken covering to endeavour to protect them 

 from the attacks of enemies ; but, alas ! who would imagine 

 a fairy fly to be an enemy ? Yet its microscopic size 

 enables it to pass unnoticed, and also permits its passing 

 beneath the silken screen, and, once there, woe betide the 

 psocid's eggs ! for the busy fairy taps one with her clubbed 

 antennEe, mounts to the summit, and then lets down 

 the ovipositor until the barbed tip touches the surface 

 of the fresh -laid egg (it must be fresh). Now by care- 

 fully focussing a good magnifier, we can observe the 

 fairy taking a firm hold of the surface of the egg with the 

 two curved tips of each of her exquisitely formed toes ! 

 Next we note that pressure is being put upon the barbed 

 ovipositor. The antennfe are pressed firmly to the surface, 

 and impress the observer with the fact that some very 

 serious business is in hand. Eleven minutes have passed 

 without any sign of a move, when just after eleven and a 

 quarter the ovipositor positively bumps through the shell. 

 There is another serious pause, and then up go the 

 clubbed antennfe,and very carefully the ovipositor is with- 

 drawn until it slips back between the sheaths. The 

 fairy turns round, and with saliva from her mouth seals 

 up the incision. Another egg is ascended, bored, and 

 stored with an egg — and so on until the whole patch of 



twenty has been struck, and all chance of any psocid 

 emerging utterly ruined. I kept the first batch of eggs 

 which I had seen struck in October until the following 

 year, when, as the warm days of April arrived, I carefully 

 examined them, until one eventful day I observed one of 

 the eggs had a tiny hole in it. On placing it under the 

 microscope I saw a pair of mandibles busily at work 

 nibbling away the egg shell, until at last the hole was 

 large enough to admit of the head being thrust through. 

 After many efi"orts the antenna were freed, followed by 

 the first pair of legs ; thon, with this additional leverage 

 at command, the thorax was lifted out, the second pair 

 of legs and part of the wings following, and after much 

 apparently painful efl'ort the third and last pair of legs 

 was withdrawn, enabling the fairy to walk out, and 

 to free those most exquisitely deUcate wings without a 

 hitch. Now, taking a firm grip on the empty egg shell, 

 the fairy went through her toilet. Not a hair or spine 

 escaped attention — each and every part of this micro- 

 scopic marvel received the utmost attention ; every hair 

 forming the lovely marginal fringe was brushed out 

 and arranged in exact order. The wings were raised 

 several times to try them, and then away this atom of 

 perfection flew. Since my first seeing the oviposition of 

 a fairy fly I have dissected many struck eggs, and in 

 less than a minute had the germ (laid by the fairy fly) 

 under my microscope, and watched it grow, and the cells 

 divide again and again in such a marvellous manner 

 that I have been lost in wonderment or simply over- 

 come. Flesh and blood is not strong enough to carry on 

 such watchings too long, but the fascination is so great 

 that time after time have I watched the mysterious 

 changes taking place — various organs being formed under 

 my eyes — the active larva gradually losing all its activity 

 until it appears in pupal form, and then new limbs and 

 organs seem to be evolved from nothing at all. 



The next genus, Litus, is a peculiar one. Its one repre- 

 sentative, Litus ci/nijisnts, much resembles a flea in colour 

 and form. It is the only fairy fly that takes its time in 

 walking. I have never seen it in a hurry, neither have I 

 ever seen the male — and the female is not a plentiful 

 species. 



EustocJnts is distinguished by having a deeply marked 

 suture across the club of the antennte, and though Haliday 

 mentions but one species I have found over a dozen ; in 

 fact, of this genus I can always find specimens anywhere 

 — on windows, in greenhouses, in railway carriages, besides 

 sweeping them up from grass and all kinds of herbage. I 

 have also seen and caught them flying, and have obtained 

 many specimens from spiders' webs. 



Ml/mar pulclullus is, without doubt, the most extra- 

 ordinary of the whole family. My first specimen I caught 

 in a spider's web when living near Finsbury Park. It was 

 very much held by viscid globules, but after many hours' 

 work appeared in Canada balsam a splendid mount. No 

 insect has exercised my power of thought more than this 

 one; but its life history remains a mystery still, though 

 I imagine I am within measurable distance of discovering 

 its nidus. Fig. 4, the male, and Fig. 5, the female, will 

 give a good idea of the surpassing delicacy of this fairy fly. 

 The posterior wings are abnormal — mere bristles — and yet 

 they are of immense service when hooked into the anterior 

 ones, the black specks just before the tips of these bristle- 

 like wings being the three booklets. {See FigJ.) In Fig. 5 

 the wings are hooked together. 



The next representative, Cosmoro/nn, is Haliday's Poli/- 

 nemri , which, he states, afi'ects the eggs of the cabbage 

 butterfly. Fig. 8 represents C. fumipennis, which is of the 

 most strikingly beautiful character. I once saw the male 



