HARDWICKE'S SCIENCE-GOSSIP. 



151 



.apterous aphides, as their ancestors had done two 

 years ago ! Hence, during the past ten days, I have 

 frequently visited this particular plant of ivy, as well 

 -as several other larger plants, which, on searching, I 

 found likewise to be infested with this same species of 

 aphis ; and I have observed the gradual increase in 

 numbers of the aphides, as also their gradual exten- 

 sion on to other plants, with other additional interest- 

 ing facts in their economy ; such as, that it is only the 

 young and tender shoots of the ivy that they attack — 

 extending themselves, not only on to the leaf-stems 

 and the under side of the leaves, but also on to the 

 adventitious roots, or rootlets, which the shoot of this 

 climbing clinging plant throws out to grasp and 

 adhere to the object over which it spreads itself ; that 

 there are at present not only apterous viviparous 

 females, but also pupa? and imagoes (winged indi- 

 viduals), as well as a majority of larvae or young ; 

 that the young are, in general, ushered into existence 

 tail foremost and dorsum uppermost, and are appar- 

 ently enclosed in an exceedingly delicate pellicle 

 which is ruptured during parturition and worked 

 backwards over the body towards the apex of the 

 abdomen, and, on its completion, is observable ruffled 

 up on the very tip or apex ; that not only are they 

 attended on and caressed by the red ant (Myrmica), 

 but also in at least equal numbers by the larger and 

 more irritable black ant (Formica), for the purpose of 

 obtaining their anal emissions of honey-dew ; and that 

 they have an active enemy in the form of a minute 

 jet-black fly with iridescent, almost veinless wings, 

 short and obtuse (though acutely pointed) abdomen, 

 and rather long, stout, clubbed, and kneed or down- 

 wardly-bent antennae, which mounts upon the back of 

 the chosen aphis, seats itself firmly with its tail 

 towards the head of it, and evidently punctures it in 

 the basal region of the abdomen, for the purpose 

 undoubtedly of inserting its egg in the body of the 

 aphis, which would shortly kick and plunge desper- 

 ately as though in great pain and wishful to unseat its 

 tormentor, while the fly would remain securely and 

 calmly seated until it had effected its purpose, when 

 it would dismount and again set out on an exploration 

 amongst the herd of aphides, examining and passing 

 over several (maybe already favoured with a visit) 

 before fixing upon another victim as a living host for 

 its carnivorous young. 



That these aphides are benefited by the attentions 

 paid to them by both species of ant, there can be 

 little doubt ; since, on the approach of an intruder, 

 the ants are on the alert, elevating the anterior part of 

 their body and widely and threateningly opening 

 ■their powerful jaws, and when a grass-stem or other 

 small object is presented to them, boldly seizing it 

 with their jaws, and allowing themselves to be carried 

 off with it ; the black ant, which is the more irritable 

 and combative, bites and apparently attempts to sting 

 the intrusive object, and will always even mount and 

 attack one's finger if ^intruded upon its milking- 



grounds. Thus, in all likelihood, predacious insects 

 will be in a measure intimidated from preying upon 

 the aphides, or laying their eggs in their bodies or 

 amongst them. On one occasion I observed on the 

 foliage of the ivy close by one of the aphid herds, 

 numerously attended on by the black ant, the small 

 parasitical fly already mentioned and partly described, 

 which would undoubtedly be there for the purpose of 

 laying its eggs in the bodies of the aphides ; and, also 

 resting near by, individuals of three different species of 

 hoverer fly, or Syrphus, possibly there for the purpose 

 of depositing their eggs on the foliage near by or 

 amongst them, the grub or larva of which is terribly 

 destructive to the aphides, rapidly clearing them off 

 an infested shoot or leaf. Few indeed of the many 

 species of aphis that I have taken note of are without 

 this latter dire enemy, which, lying at its ease in the 

 midst of the host or herd, feeds and fattens at its 

 expense, and thus proves itself one of the best insect 

 friends of the gardener and horticulturist, by 

 effectually checking the increase of these too 

 frequently injurious little creatures. 



Though the different individuals of the same species 

 of these two ants always attended on and milked the 

 aphides in evident harmony, however crowded they 

 might be — and I have seen from ten to sixteen of the 

 red ants all engaged at once upon the aphides cloth- 

 ing not more than three inches of an infested shoot ! 

 — yet I never observed the two species upon a 

 common milking-ground. Wishful to see what effect 

 would be produced upon the individuals of one 

 species by the introduction of one of the other, 

 I took a red ant and placed it upon a shoot upon 

 which were three black ants attendant upon a few 

 aphides : it was immediately attacked by all the three, 

 and a good deal of very evident reciprocal biting and 

 attempted stinging went on between it and its three 

 larger congeners ; however, it at last managed to 

 escape from them, apparently not much the worse 

 for the very rough handling to which it had been 

 subjected. Charles Robson. 



Elswick, Neivastle-npon- Tyne. 



Erratum. — In my former paper (" Oviposition 

 and Description of the Ivy Aphis "), in the May issue 

 of Science-Gossip, at line nine, page 105, for 

 aphides in feeding them read aphides infesting them. — 

 C.R. 



Slow-Worm. — I do not think Miss Kingsford's 

 pets will thrive without their natural food, i.e. the 

 small slugs found in a garden. I never fed mine with 

 anything else, and it is not difficult to find them in 

 damp spots, or, indeed, anywhere in wet weather. The 

 common snake should be fed with live frogs (if there 

 are no anti-vivisectionists in the neighbourhood), but 

 very often they refuse all food, and cannot be kept 

 alive.— II. UUyett. 



