popular 



of 



83 



during summer and autumn. The spawn is 

 shed in the beginning of winter in deep water; 

 and it retreats altogether from our shores in 

 severely cold weather. The young of this fish 

 are commonly known by the name of Chads. 

 The Sea bream is iiot very highly esteemed 

 for the table, either fresh or salted. 



BREEZE-FLY. ((Estrus; (Estridce.) The 

 insects we are about to describe are produced 

 from larvae which when existing in horses 

 are termed bots ; in sheep, maggots ; and in 

 cows and oxen, wornils; and these three 

 represent three divisions of the family, dif- 

 fering essentially in their history. The per- 

 fect insect produced from each kind of larva 

 is properly termed a Breeze-fly. Before we 

 proceed farther, however, we beg to state 

 that the observations which follow are taken 

 from Mr. Newman's History of Insects, who 

 quotes as his authority " An Essay on the 

 Bots of Horses and other animals, by Bracy 

 Clark, F.L.S." 



" The opinions of the Breeze-fly of the 

 horse, or bot, as it is usually termed, as to the 

 benefit or injury derived from it, are very 

 opposite ; some observers go so far as to as- 

 sert that the larvae occasionally completely 

 perforate the stomach of the horse, causing 

 disease, pain, and even death j others regard 

 them as perfectly innocuous ; and one author 

 [Mr. Bracy Clark], whose careful and labo- 

 rious investigations entitle his opinions to 

 the greatest respect, believes the effect of 

 bots to be salutiferous rather than otherwise; 

 and from his masterly essay the following 

 particulars are extracted. 



" The female fly, in approaching the horse 

 for the purpose of pviposition, carries her 

 body nearly upright in the air, the protruded 

 ovipositor being curved inwards and up- 

 wards. Suspending herself for a few seconds 

 before the part of the horse on which she 

 intends to deposit the egg, she suddenly 

 darts upon it, and leaves the egg adhering 

 to the hair : she hardly appears to settle, 

 but merely touches the hair with the egg 

 held out on the extreme point of the ovi- 

 positor, the egg adhering by means of a glu- 

 tinous liquor with which it is covered. She 

 then leaves the horse at a small distance, 

 prepares a second egg, and, poising her- 

 self before the part, deposits it in the same 

 way : the liquor dries, and the egg becomes 

 firmly glued to the hair. This is repeated 

 till four or five hundred eggs are sometimes 

 placed on one horse. The skin of the horse 

 is usually thrown into a tremulous motion 

 on the touch of the insect, which merely 

 arises from the very great irritability of the 

 skin and cutaneous muscles at this season of 

 the year, occasioned by the heat and con- 

 tinual teasing of the flies, till at length these 

 muscles appear to act involuntarily on the 

 slightest touch of any body whatever. 



" The fly does not deposit her eggs at lan- 

 dom on the horse's body, but selects those 

 parts which are most likely to be nibbled 

 by the horse : the inside of the knee is fre- 

 quently chosen, but all naturalists must 

 have remarked how commonly the eggs of 

 the bot are deposited on that part of a horse's 

 shoulder which he can never reach with his 



month, and thus, to a casual observer, it 

 would seem that they must perish, and fail 

 in the object for which their parent designed 

 them. Now there is a provision of nature 

 which exactly counteracts this difficulty. 

 When horses are together in a pasture, and 

 one of them feels an irritation on any part 

 of the neck or shoulder which he cannot 

 reach with his mouth, he will nibble another 

 horse in the corresponding part of his neck 

 or shoulder, and the horse so nibbled will 

 immediately i>erfonn the kind office re- 

 quired, and begin nibbling away in the part 

 indicated. The horses, when they become 

 used to this fly, and find it does them no 

 injury by sucking their blood, hardly regard 

 it, and do not appear at all aware of its 

 object. 



" When the eggs have remained on the 

 hairs four or five days, they become mature, 

 after which time the slightest application of 

 warmth and moisture is sufficient to bring 

 forth in an instant the latent larva. At this 

 time, if the lips or tongue of the horse touch 

 the egg, its operculum is thrown open, and 

 the young larva liberated : this readily 

 adheres to the moist surface of the tongue, 

 and is from thence conveyed with the food 

 to the stomach. It is worthy of remark, 

 that it is probable the greater part of the 

 eggs deposited by this fly are taken up in 

 consequence of the irritation of other flies, 

 as the 7 ii/tinii and Stomaxidcs, which, by 

 perpetually settling on the skin, occasion a 

 horse to nibble himself on those parts, and 

 thus receive the larvae on the tongue and 

 lips, whence they are introduced into the 

 stomach. * * * The larva, when matured, 

 quits the stomach of the animal and falls to 

 the ground, and finding a convenient place 

 of retreat, undergoes its change to a chrysalis, 

 the skin then losing its organization, and 

 changing in colour from a whitish red to a 

 reddish brown. After remaining torpid in 

 the chrysalis state a few weeks, the super- 

 fluous moisture being removed and the 

 parts of the future insect hardened by drying, 

 it bursts from its confinement, and the fly 

 makes its exit at the small end of the case. 

 A few hours after quitting their shell they 

 become dry, take wing, and seek their mates. 



"A second species of Breeze-fly. has a still 

 more wonderful history : its eggs are laid in 

 the nostrils of sheep, from one to seven or 

 c'ght in each individual, and these on be- 

 coming larvse.enter the frontal and maxillary 

 sinuses, and even the horns, and feed on 

 their secretions : when the larvae are young 

 they are perfectly white and transparent, 

 except two small black horny plates : as 

 they increase in size the upper surface be- 

 comes marked with two transverse brown 

 lines on each segment, the anterior being 

 shorter and narrower than the posterior ; 

 and some spots are also observable on the 

 sides. The body consists of twelve segments 

 besides the head. These larvae move with 

 considerable activity, holding with their 

 tentacula to a fixed point and drawing up 

 the body. When full grown the larvae fall 

 through the nostrils of the sheep, and change 

 to the pupa state lying on the earth or ad- 

 hering to the side of a blade of grass : in 



