HIPPOBOSCA. 



HIPPOCREPIS. 



90 



oi-dinarily bent backwards and hidden almost entirely between the 

 month and the external jaw-feet. The first joint of their peduncle is 

 small and but little apparent ; the second is large and armed ante- 

 riorly with two spiniform teeth, the external of which ia much the 

 strongest ; the two succeeding joints are small, and form by their 

 union a globular mass, whence springs a last peduncular joint, which 

 is cylindrical, and supports in ita turn the multi-articulate terminal 

 filament, which last is very large, nearly of the length of the carapace, 

 and fringed externally with a double row of long hairs. The external 

 jaw-feet are of considerable size and operculiform, but their first two 

 joints are very small, and it is the third only which presents that 

 disposition ; the last three joints form a long, delicate, and lamellar 

 appendage, which is inserted in a notch of the external angle of the 

 preceding joint, and is bent back under its internal edge, but Joes not 

 constitute a claw as in Remipes. The palp of the two pairs of suc- 

 ceeding jaw-feet is terminated by a lamellar enlargeaient. The feet 

 are short, and hidden under the carapace ; the first pair are stout and 

 applied against the mouth, terminating with a ciliated nearly oval 

 1 uiiina. The tarsus of the two succeeding pairs of feet is lamellar and 

 hastiform, and that of the fourth pair is stout, conical, and very short. 

 The posterior feet, which are long, membranous, and very slender, 

 are bent back between the lateral part of the carapace and the base 

 of the preceding feet. The last thoracic ring is not free and exposed 

 as in Hemipei ; but the first joint of the abdomen is nearly of the 

 Bame form, and the succeeding rings present also the disposition 

 already noticed in these crustaceans. (Milne-Edwards.) 



Hippo, Emerita is the best example. The length of this species is 

 from 1 inch to 15 lines. It inhabit-* the coasts of Brazil. 



Hifipa Emerita. 



HIPPOBOSCA. [HIPPOBOSCID.E.] 



HIPPOBOSCIDjE, a family of Dipterous Insects belonging to the 

 ectiou Pupipara or order Homalopttra, containing the Forest-Flies, 

 which exhibit such remarkable variations in their typical structure 

 that they have been regarded by some authors as forming a distinct 

 order. The head is received into a cavity in front of the thorax ; it 

 is divided transversely into two parts, the anterior or smaller of which 

 supports the mouth and two small tubercles, almost imbedded at the 

 lateral angles, being rudimental antennae. The mouth is composed of 

 two curved seta;, inclosed in a tubular canal, covered by two narrow 

 elongated coriaceous plates, regarded by Latreille as palpi. The 

 ocelli are wanting. The body is short, flat, and very coriaceous; the 

 wings are either large or entirely wanting ; the nervures of the anterior 

 margin are very strong, but they are effaced behind. In the winged 

 species a pair of balancers are also present. The legs are very strong, 

 and terminated by robust curved claws, which are toothed beneath. 

 The abdomen is composed of a continuous leathery-like membrane, 

 capable of very great distension, which peculiarity is owing to the 

 remarkable circumstance that the young of these insects are singly 

 nourished within the body of the parent, where they not only acquire 

 their full size, but actually assume the pupa state, under which form, 

 like very large eggs, they are deposited by the female. This egg-like 

 cocoon is at first soft and white, nearly as large as the abdomen of 

 the parent fly ; but by degrees it hardens, becomes brown, of a rounded 

 form, and often notched at one end, which is covered by a shining kind 

 n( cap, which is detached on the insect's assuming the perfect state. 

 Tlii -i cocoon is moreover entirely destitute of annular incisions, in 

 which respect it differs from those of other Dipterous Insects. It is 

 composed of the uncast skin of the larva, beneath which the insect 

 becomes a real inactive pupa, with the limbs of the perfect insect laid 

 along the breast, as in othtr species which undergo the strict coarctate 

 i of transformation. H. Reaumur was the first to discover these 

 curious particulars ; and ha wag ao anxious to observe the develop- 



ment of the insect from these singular eggs, that he carried them in 

 liis pocket by day and took them to bed witb him at night, in order 

 that they might have a uniform degree of warmth ; great was his 

 surprise therefore when, instead of grubs as he expected, perfect flies 

 were produced. 



These insects are interesting in their habits. They live exclusively 

 upon quadrupeds and birds ; the horse is especially subject to the 

 attacks of one of these species, hence called Hippobosca equina. This 

 species is the type of the genus Hippobosca, in which the eyes are large 

 and distinct, being placed at tha sides of the head ; the antenna: are in 

 the shape of turbarcles with three dorsal setae ; the wings are large. Mr. 

 Curtis observes that these flies move swiftly, and like a crab, sideways 

 or backwards ; they are very tenacious of life, and live principally on 

 horses, attaching themselves to the belly between the hind thighs and 

 under the tail, where they are less protected by hair. It is remarked 

 by Latreille that the ass fears them most, and that horses suffer 

 very little from them. In the New Forest they abound in a most 

 astonishing degree. Mr. Samouelle says, "From the flanks of one horse 

 I have obtained six handsful, which consisted of upwards of a hundred 

 specimens. They abound most on white and light-coloured horses." 



The other genera are : ' Ornithomyia, Craterina, Oxypterum, 

 ffcemoboi'a, Melophagia, Feronia, Lipotepna, and probably Braula. 

 Of these the first three are British, and are found upon various birds, 

 the Craterina hirundinis depositing its egg like a cocoon in the nest 

 of the swallow, where it receives all the necessary warmth ; for which 

 it repays the poor swallow by sucking its blood.' The wings in this 

 genus are very long and narrow. The genus Mdophayus comprises a 

 single species, M. (minus, which is destitute of wings, and attacks the 

 sheep. It is of a dark reddish colour, with the abdomen whitish. 

 It is commonly called the Sheep-Louse, and is so tenacious of life 

 that Kay states that it will exist in a fleece twelve months after it is 

 shorn, its excrements even giving a tinge to the wool, which is very 

 difficult to be discharged. 



HIPPOBRO'MA (from '/nroi, a horse, and 0pw/xa, food), a genus of 

 Plants belonging to the natural order Lobeliacete. It has the limb 

 of the calyx 5-parted with linear segments ; the tube of the corolla 

 long, straight, entire, with the limb 5-parted, nearly equal; the 

 stamen-tube projecting, completely monadelphous and syngeuesious ; 

 the stigma sloped, the capsule 2-celled, 2-valved, many-seeded. 



H. longiflorit is the only species. It is an herbaceous plant, with 

 short axillary pedicels, mucronate or coarsely toothed leaves, with 

 long slender white flowers. It is a native of Jamaica, St. Domingo, 

 Cuba, and Martinique, in damp places and by the side of streams. 

 This is one of the most poisonous of plants. If the juice only acci- 

 dentally touches the lips or eyes it produces a burning inflamma- 

 tion. Horses are violently purged after eating it. 



(Don, Dichlamydeova Plants ; Liudley, flora Medica.) 



HIPPOCAMPUS. [SYNGNATHID.E.] 



HIPPOCEPHALOI'DES. By this name Plott and other writers 

 understood the inner casts of certain equivalved Conchifi.ra, espe- 

 cially Trigonia, 



HIPPOCRA'TEA, a genus of Plants belonging to the natural order 

 Hippocrateacece, so named after Hippocrates, and which might there- 

 fore be expected to contain many useful or medicinal plants. But it 

 is not so. The species consist of moderate-sized trees, which are 

 found in the hot parts of the world, as in the tropical parts of 

 America, in Sierra Leone, the warmer parts of India, and the Island 

 of Timor. The genus is characterised by having the calyx 5-leaved, 

 but very small ; petals 5, usually hooded at the apex ; stamens 3, 

 anthers 1-celled, opening transversely at the apex ; carpels 3, samaroid, 

 bivalved, valves keeled and compressed ; seeds winged from the 

 funicnlus being widely expanded. The fruit of some of the plants 

 of the family is eatable ; but the seeds of one species only of 

 Hippocratea are mentioned as being of any use ; those of //. comosa, 

 being oily and sweet. 



HIPPOCRATEA'CEvE, a small natural order of Exogenous Plants 

 remarkable for the presence of three monadelphous stamens in a 

 pentapetalous flower. The fruit consists of from one to three cells, 

 and is frequently extended at the back in a membranous manner, so 

 as to resemble the samara, or key of the ash-tree. The species are 

 woody, and often climbers ; they inhabit Africa, the Mauritius, and 

 the tropical parts of America ; in general they are of no importance 

 for economical or medical purposes. The fruit of Tonsella j,yriformis 

 is eaten in Sierra Leoue. The nuts of Jlippocralea comosa are oily 

 and sweet. They are called in the French West India Islands 

 Amaudier du Bois. In Brazil other species have eatable fruits. The 

 order has 6 genera and 86 species. They are related to Chailletiacut, 

 Cdastracece, Malpiyhiacece, and Aceracece. 



HIPPOCRE'PIS (from SWoj, a horse, and Kprj-iris, a shoe, on account 

 of the curved shape of its pods), a genus of Plants belonging to the 

 natural order Leguminoace, the tribe Uedysareas. It has diadelphous 

 stamens, an acute style ; the legume curved, with numerous 

 1-seeded joints ; the seeds cylindrical or compressed, oblong, curved, 

 fixed to the middle part of the joint, and therefore the umbilicus is 

 in the middle of the curve. The species are herbs, or umler-shrubs, 

 with unequally pinnate leaves and yellow flowers, which are some- 

 times solitary and axillary, sometimes sessile, but usually disposed iu 

 umbels on the tops of the axillary peduncles. 



