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47. Note on Myriapoda. I send you an account of " Observations sur les Myi'ia- 

 podes, par M. A. F. Waga, Professeur d'Histoire Naturelle, a Varsovie," published in 

 the ' Revue Zoologique, ' thinking it may be interesting ; and I have added thereto 

 some remarks that I have made. Prof. Waga says they are easily kept and reared in 

 a jar containing some earth, and a few dead and decayed leaves (which must be oc- 

 casionally moistened) for food. They dislike light ; and if their food be not changed, 

 they grow weak and diseased, and are covered with innumerable Acari, which increase 

 in number daily till the creature dies. Though usually inhabiting damp situations, 

 they choose a dry spot when they change the skin. Of all Chilognatha Craspedoso- 

 ma has most fondness for damp, and dwells only in spots that are almost marshy, and is 

 therefore not able to find a dry spot whereon to change its skin, but placing itself be- 

 tween two leaves, it spins on one of them a cocoon that resists the outward damp, and 

 then rolls itself in a spiral form and changes its skin. The Juli have, on each side of 

 the body, a series of pores, which Waga calls ^''foramina repugnatoria" for through 

 them is emitted a volatile oil, by which the insect defends itself. The Geophili emit 

 an electrical smell by these pores, and Geophilus electricus has the power of ejecting 

 by them a liquid, shining in the dark. Julus terrestris has 60 abdominal segments 

 and 182 legs, four to each segment, but two of the posterior and one of the anterior 

 segments have no legs, and there are three segments that have each only a single pair 

 of legs. Some of the Myriapoda (e, g. Platyula) take their food by suction, and M. 

 Brandt has separated them from the Chilognatha, and named them Siphonizantia. 

 The food of the Chilognatha is not confined to vegetable matter, but they also devour 

 small MoUusca (Helix, Vitrina and Clausilia), and the pupae of small Coleoptera, and 

 also the Lumbrici or earth-worms, which in their turn feed on the dead Chilognatha. 

 Craspedosoma is infested by the larva of one of the Stratiomydae. Waga states that 

 it is certain that the Geophili, like the Lumbrici, subsist entirely on vegetable earth. 

 He observed that the eggs of Julus unciger are oval and of a yellowish white colour, 

 and that when they split into two equal parts the young ones are seen inside, milk- 

 white, very soft, and without any limbs. In four or five days the antennae and the three 

 simple pairs of legs become visible, I have often observed the young of Polydesmus 

 in this state, that is varying in length from | to ^ a line, and having only 6 legs and as 

 many segments, including the head. It is white and seraitranspareut, like glass with a 

 milky hue. When little more than a line in length it has 10 segments and the same num- 

 ber of legs on either side of the body. Waga remarks that the young Juli afterwards have 

 7 segments, then 8 besides the head, and they then have 2 double pairs of legs, mak- 

 ing 14 in all. When full grown the insect has 30 legs, 3 single and 6 double pairs. 

 Many of the legs are not developed till the animal has shed its skin. I have observed 

 that Julus pulchellus, when about 2 lines in length, has 14 legs or thereabouts on ei- 

 ther side of the body, which is composed of nearly the same number of segments. The 

 legs do not then extend along the whole length of the body, there are a few segments 

 at either end on which they are wanting, especially towards the tail, where the seg- 

 ments are furnished with bristles instead of legs. It is white and semi transparent. 

 When a little larger it acquires 4 additional legs on either side. Each segment has 

 a red spot on either side ; but when the creature is young it is only one segment that 

 is thus adorned. These spots contain a coloured liquid, which exudes from the body. 

 Julus terrestris in like manner emits a dark purple liquid when thrown into hot water. 

 — Francis Walker ; 49, Bedford Square, Juhj 18, 1841. 



48. Aphis of the Peach. In all stages of growth during May, beneath the leaves 



