276 



PULEX.- 



-INSECTS.- 



-Araciinipa. 



pain, is succeeded by a tickling and not disagreeable sen- 

 sation, occasioned by the insect sucking its sanguineous 

 draught. The female lays a number of oval eggs of 

 pure white colour, selecting frequently a hearth-rug, 

 carpet, or chair cushion ; at other times she deposits 

 them in dusty cracks in the floor. The larva; are long 

 slender thread-like worms which, when full grown, spin 

 and inclose themselves in silken cocoons. 



The species that attacks man is the Piilex irritans, 

 a figure of which is given on Plate 11, figs. 15, 16, 

 Althougli sufficiently numerous in this country, parti- 

 cularly in dirty houses and amongst people of dirty 

 liahits, little idea of the multitudinous hosts in which 

 they swarm in hotter parts of the globe can be formed, 

 until the traveller makes their acquaintance in favoured 

 localities. We have been told that they skip about in 

 the streets of Naples by thousands ; on the shores of 

 its lovely bay they assemble in myriads; and in all con- 

 tinental churches they abound, particularly under the 

 dome of the magnificent church of St. Peter at Rome. 



A particular and distinct species attacks the dog, but 

 the same species is found on the cat, arid it freely 

 attacks man himself. This is the Pulcx canis. 



A distinct species is found on the cat, and no doubt 

 were the subject pursued, many distinct species esist 

 attached to dilferent animals. A much more formi- 

 dable insect than the flea is found in the West Indies, 

 popularly known in those latitudes as the Cliigce 

 (Sarcopsylla jnnetrans), Plate 11, figs. 11, 12. Mr. 

 Waterton in his " Wanderings" says, " It looks exactly 

 like a small flea, and a stranger would take it for one ; 

 it attacks dilferent parts of the bod}', but chiefly the 

 feet, betwixt the toe nails and the flesh. There it 

 buries itself, and at first causes an itching not unplea- 

 sant. In a day or two you perceive a place about the 

 size of a pea, somewhat discoloured ; this is the nest 

 of the Chigoe, containing a hundred eggs, and if 

 allowed to hatch there the young ones will soon begin 

 to form other nests, and in time cause a spreading 

 ulcer. As soon as you perceive that you have got a 

 chigoe in your flesh, with a sharp-pointed needle or knife 

 you must take it out." Neglect of the latter precaution 

 is followed by most serious results. It would appear 

 that the attack of this insect on persons of inflammatory 

 habit, has frequently been followed by fever and groat 

 suU'ering and pain. 



Class-ARAGHNIDA. 



This class of articulated animals contains the spiders, 

 scorpions, and mites ; the spiders forming the order 

 Araneidea. A concise summary of their organization 

 and economy is all that our limited space will allow. 



In spiders uo distinct head, as in insects, wfll be 

 observed ; it is, as it were, merged into and ai)parently 

 forms a part of the thorax, hence called the cephalo- 

 thorax, the head and thorax being contiunouR ; there 

 are few exceptions to this rule. Spiders have no 

 antenn.T, and nearly all have eight legs ; a few have 

 six, and others ten. On the anterior, or cephalic portion 

 of the thorax, are situated the eyes; these are eight, six, 

 or two in number. Those organs which are used for 

 seizing, and which in insects would be called mamhblcs, 

 are in spiders called falces; these are situated in front, 

 and are usually terminated by a sharp hook or fang. 

 The legs are eight-jointed, having two or more claws 

 at their apex. Their abdomen is soft, usually globular, 

 but in some species oblong ; it is in one piece, never 

 having segments .as in insects ; at its apex beneath are 

 six or eight fleshy mammulaB or spiracles ; it is from 

 these that the silk issues, when the animal is spinning. 

 All spiders have eyes; they are smooth, and as observed 

 above, dilTer in number ; they also diO'er much in size 

 and position, and from this circumstance important char- 

 acters for their systematic arrangement are derived. 



The falces, although modified in form in different 

 species, are usually subconieal, having at the extremity 

 within, a longitudinal groove, the sides of which are 

 dentate ; this groove receives the fang when in repose. 

 The claw or fang is hard, and acute at the point, near 

 to which is a small oijening which emits a colourless 

 fluid ; this, in some species, appears to be of a poisonous 

 nature. 



The falces are the organs in spiders which are used 



to seize and hold their prey. Spiders are extremely 

 voracious, but are capable of enduring the want of food 

 for a very long period ; some species have been known 

 to live from six to eight months without nutriment. 

 In no animal apparently is tlie sense of touch so fine as 

 in the spider; and on this sense much more than on sight, 

 do many species depend for ascertaining the presence 

 of insects, upon which they prey. The poet has finely 

 described the sense of touch in spiders, which he says, 

 "lies in each thread, and lives along the line." The 

 accuracy of this description m.ay be proved by any one 

 who will notice a species of spider that spreads its 

 geometric net on plants, from which many lines will be 

 seen to converge to tlie mouth of its den ; this will bo 

 in some hole in an old wall, &o. No sooner docs an 

 insect touch any part of the net, or of the silken cords 

 that retain it in its position, than the spider through the 

 delicac}' of his sense of touch becomes instantly aware 

 of its presence ; the garden spider, Epcira dkidemii, 

 may always be tempted out of its hiding-place by 

 touching its web lightly with a twig or straw. — Fig. 177. 



Spiders have been ascertained to undergo several 

 moult.ings, subsequently to the time when they first escape 

 from the egg, and before they arrive at maturity; some 

 have been known to moult five, others as many as nine 

 times. They also possess the power of reproducing limbs 

 that have become mutilated, or which they have alto- 

 gether lost; b\it this capability does not appear to have 

 been observed in such as have arrived at maturity. 



Any account of the economy of spiders, approaching 

 even a satisfactory sketch of their history, would occupy 

 a bulky volume ; a few general observations is all tliat 

 can here be attempted. Some species burrow, or 

 excavate dens or holes in the ground ; these are of a 

 cylindrical shape, and are lined with a thick tissue of 



