346 



OIL NUT OLACINE^. 



pool of water, where they are safe from the attacks 

 of the insect. But the most curious part of the sub- 

 ject is, that this dread is* merely instinctive. The 

 oestrus inflicts no pain whilst in the act of depositing 

 its egg, for it now seems decisively proved that the 

 old account, that the ovipositor of the insect was 

 capable of inflicting, and in fact inflicted, a wound for 

 the reception of each egg, is unfounded, and that the 

 eggs are merely glued by the out-stretched ovipositor 

 of the female fly upon tne hair of the back of the ox. 

 No sooner is the larva hatched than, according to 

 Mr. Bracy Clark, it burrows into the skin, and soon 

 forms around itself a bump or protuberance upon the 

 animal's back a place, as Reaumur observes, where 

 food is found in abundance, where it is protected 

 from the weather, where it enjoys at all times an equal 

 degree of warmth, and where it finally attains matu- 

 rity. Reaumur has given a very detailed account of 

 the habits of this insect ; but admits that he never 

 saw a female deposit her eggs, so that his supposition 

 as to the parent fly piercing the skin of the ox does not 

 rest upon direct observation, and is contradicted both 

 by the texture of the ovipositor itself, and the state- 

 ments of Mr. Clark. These larvae are called warbles 

 or wurmals, their habitations increasing in size accord- 

 ing to the growth of the inclosed larvae ; the largest 

 are nearly an inch and a half in diameter at the base, 

 and about an inch high; they are scarcely perceptible 

 externally during the winter, but attain their full size 

 by the beginning of the summer. It is necessary that 

 the tumour should have an orifice for the supply of 

 air to the larva, and the situation of the spiracles is 

 precisely that which is most admirably adapted for 

 the nature of the habitation of the insect ; had the 

 spiracles been disposed along the sides of the body, 

 as is their general situation, it would have been 

 necessary that an open space should have been main- 

 tained around the body of the insect, but they are 

 placed at the hinder extremity of the body, 

 which is kept constantly applied to the orifice, which 

 it exactly fits, and by this means not only is the aper- 

 ture closed but a supply of air is maintained, and the 

 head of the insect is placed at the greatest distance 

 from the surface, and consequently most deeply into 

 the flesh, where of course it obtains a great supply of 

 food, which consists of pus, or matter secreted in 

 consequence of the irritation produced by the insect. 

 It is commonly upon the young cattle of two or 

 three years old that they are found ; they seldom 

 attack old animals. The number of bumps upon an 

 ox is various ; in some not more than three or four 

 are to be found, whilst in others as many as thirty or 

 forty may be discovered. They are generally placed 

 near the spine, but sometimes upon the thighs and 

 shoulders ; sometimes they are far apart, whilst 

 occasionally several of them are so close as to touch 

 each other. It must be evident, that if these larvae 

 fed upon the flesh of the beast the presence of so great 

 a number must be .attended with the greatest pain 

 and suffering, but so far is this from being the case, 

 that it would appear that they do the ox no material 

 injury, and occasion none or but very little pain ; 

 indeed cattle most covered with bumps are not con- 

 sidered by the farmer as injured, the warbles being 

 regarded as proof of the goodness of the animal, since 

 these flies attack only young and healthy oxen. The 

 tanners also prefer those hides which have the greatest 

 number of warble holes in them, which are always 

 the best and strongest. 



The oestrus of the sheep which, from its larva inha- 

 biting the frontal sinus of that animal, has been 

 appropriately formed into the genus C'cphalcmyia by 

 Latreille, is of a smaller size than the foregoing, being 

 not more than five lines long, and of a greyish colour. 

 The dread produced by the presence of this insect is 

 exhibited in a different manner to that caused by the 

 ox oestrus. The sheep shake their heads and strike 

 the ground violently with their forelegs, or, running 

 away, get into ruts, dry dusty spots, or gravel pits, 

 where, crowding together, they hold their noses to the 

 ground. The object of all this is to prevent the oestrus 

 from depositing its eggs in the inner margin of the 

 nostrils, whence the larvae, when hatched, ascend into 

 the head, feeding in the maxillary and frontal sinuses 

 on the mucilage there produced. When full grown 

 they fall through the nostrils, and assume the pupa 

 state on the ground. The CEstrus trompe, of Fabri- 

 cius, inhabits the same situations in the rein-deer. 



It appears certain, from numerous recent observa- 

 tions, either that there is a species of this family 

 appropriated to man, or that, under certain circum- 

 stances, man is attacked by some of those insects which 

 ordinarily infest quadrupeds. Gmelin, indeed, has 

 introduced a species into the Systema Naturae, under 

 the name of CEstrus hominis, with the observation, 

 " Habitat larva in America Australi per sex menses 

 sub cute homiuum abdominali, turbetur profundius 

 penetrando periculosa, adeo ut fertur, lethalis ; imago 

 muscae domesticae magnitudine." The larva of this 

 insect is found in South America, where, for a period of 

 six months, it burrows beneath the skin of the abdomen 

 of the inhabitants, penetrating deeper when disturbed, 

 so as to become very dangerous, and, as it is said, to 

 cause death, the imago being of the size of the do- 

 mestic fly. Latreille also states, that M. De Hum- 

 boldt noticed, in South America, Indians whose bellies 

 were covered with small tumours, produced, as he 

 supposed, by the larvae of an oestrus, most probably 

 belonging to the genus Cuterebra of Clerck. The 

 same statement is also made in the Essai sur la Geo- 

 graphie des Plantes, p. 136, by Humboldt and Bon- 

 pland. See also the Bulletin des Sciences Naturelles, 

 1823 ; the 27th number of the Magazine of Natural 

 History ; the Annales de la Societe Entomologique 

 de France for 1833 (wherein is a valuable memoir by 

 M. Geoffroy Saint Hilaire), and the Medical Journal 

 for 1835 ; in which works various notices upon this 

 subject are to be found, but of which want of space 

 compels us to omit further notice. 



The family is divided by Latreille as follows : 



A. Proboscis distinct, but very small and retractile. 



genera Cuterebra and Cephenemyia. 



B. Proboscis wanting. 



a. Palpi two. (Edemagena (CEstrus tarandi). 



b. Palpi wanting. 



Genera Hypoderma, Latreille (CEstrus bovis) ; 

 GasterophUus, Leach (Gastrus, Meig.; CEsfrus, 

 Latreille ; CEstrus Equi) ; Cephalemyia (CEs- 

 trus ovis). 



OIL NUT is the Hamiltonia oleifera of Muhlen- 

 berg, a genus belonging to Santalacecs, formerly the 

 Pyrularia pubera of Michaux. 



OLACINE^E. A small natural order of plants, 

 containing four genera and six species. The genera 

 are Qlax, Spcrmaxylon, Heisteria, and Ximenia. The 

 Olacacece, as this order is called by some authors, are 

 arborescent plants, with alternate entire simple leaves ; 

 sometimes the foliage is abortive, and the stipules are 



