148 ZOOLOGY. 



each side. There are two stemmata ; the mouth is provided with a tongue, 

 two lancet-shaped palpi, and a pair of long slender mandibles with serrulate 

 edges. The maxillary palpi have four articulations, and are so long that 

 they resemble antenna? (the antennae being inconspicuous), and below these 

 there are two maxilla, shaped like triangular plates. The antenna? are 

 minute, situated behind the stemmata, and capable of being hidden in a 

 cavity. The feet are long and bristly, and adapted for leaping, and the 

 tarsi are pentamerous. The larva of the flea is a slender white active grub, 

 without feet, but it is jjrovided with antennte, and a pair of posterior hooks. 

 It attains its full size in about twelve days, when it spins a silken cocoon, 

 and becomes a quiet pupa, in which the limbs of the imago are visible. 



Fleas {Pulex irritans^ ])l. TT,^«/. 73 ah) abound where there are dogs 

 and hogs ; in camps and barracks, where they often swarm in the quarters 

 of the soldiers. The larva seems not to be parasitic, living upon the litter 

 of stables, &c. They are often produced from eggs laid under the toenails, 

 or in the seams of the drawers of uncleanly persons, where they find 

 nourishment adapted to their wants. 



Pulex penetrans {pi. 7Y, fig. 72 ah cd), the tyj^e of Guerin's genus 

 Dermatojjhilus, is a small species which lives parasitically beneath the skin 

 of the feet of men and dogs in the warm parts of America, particularly 

 Guiana and Brazil. It is known as the jigger (chegoe, chigo), and by a 

 dozen other names. It is found in sandy places, where it hops about like 

 the other species, until it finds a suitable resting-place, when it penetrates 

 beneath the skin and forms serious sores. In this condition the abdomen 

 of the female enlarges to the size of a small pea {fig. 72 <?, enlarged and 

 inverted), and is found to be full of eggs. The male has not been observed, 

 and isg^robably not parasitic. They frequently lodge in the toes, especially 

 beneath the nails, causing great pain and inflammation, and it sometimes 

 happens that the toes must be amputated, in consequence of the sores to 

 which they give rise. Watertou saw the foot of a negro which was a mass 

 of ulcers from the neglected attacks of this insect. According to this 

 author, " The Indian and Kegro wenches perform the operation of extract- 

 ing chegoes with surprising skill. They take a pin, and by a very slow 

 process, they lay the part bare, and contrive to work quite round the bag 

 which contains the chegoe and its oflspring. As soon as this has been 

 eifected, they turn the bag out, whole and uninjured ; by which means none 

 are left in the hole to form a new colony." Besides man and dogs, the 

 sand flea attacks sheep, goats, cats, hogs, oxen, horses and asses. Accord- 

 ing to Azara, it does not extend beyond 29° of south latitude. 



Order 4. Coleoptera {2)1. 81, figs. 84-148). This order includes all the 

 insects with thin membranous wängs on the metathorax, covered by hard cori- 

 aceous wing-covers or elytra attached to the mesothorax, their color and texture 

 having more or less resemblance to the general exterior surface of the body. 

 The mouth is mandibulate, and the wings folded transversely to allow them to 

 be withdrawn beneath the elytra. There are, however, exceptions to most of 

 the characters by which groups in the animal kingdom are defined. The wings, 

 and even the elytra, are sometimes wanting. The elytra, which unite in a 

 352 



