116 BOTS IN HORSES 



century after century, and age after age ; every moment since " the spirit 

 of God moved upon the waters," that miglaty ocean has never ceased 

 its everlasting rollings to and fro — an awful fact. Let the vain sceptic 

 go to the beach, — let him shut his eyes to all the glory, and magnifi- 

 cence, and infinity before him ; let him even forget its faith and grati- 

 tude, as he sees its vapory incense ascending incessantly to the skies — 

 but let him, discarding every thing else that is grand and awful around 

 him, see and think only of the everlasting motion of the tides, in and 

 out, and then say — " There is no God." He must be a fool indeed ! 

 College of St. James'', Md., March, 1845. 



BOTS IN HORSES AND OTHER ANIMALS. NO. I. 



GENUS OESTRUS. LIN. 



Oxen, sheep and horses are subject to the annoyances of certain 

 parasitic insects, vulgarly called Bots, which I design briefly to con- 

 sider in these communications. The extraordinary means the perfect 

 insects pursue in depositing their eggs, the situations the larvae or grubs 

 inhabit, and the very high temperature to which they are exposed, rea- 

 der their history very interesting. 



The hots of the ox (Oestrus hovis,) live under the skin of the an- 

 imal, being situated between it and the cellular membrane, in a sack or 

 abscess, which is rather larger than the insect, and by narrowing up- 

 wards opens externally to the air by a small aperture. This grub is 

 entirely difterent from that which inhabits the stomach of the horse, 

 and, of course, the fly produced by it is different. Even Linne thought 

 they were the same, but the illustrious Swede himself sometimes erred. 



This larva having arrived at its full growth, efl^ects its escape from 

 the abscess, by pressing against the external opening, and falls from the 

 back of the ox to the ground, where, seeking a convenient retreat, it 

 becomes a chrysalis., and in a few weeks the perfect fly is disclosed. 

 Cattle are extremely terrified when attacked by this fly, and sometimes 

 the agitation is communicated to the whole herd. The classical reader 

 will find a lively description of such a scene in Virgil's Georg., lib. III. 

 ver. 146—151.' 



The heifers, steers, and younger cattle, are most frequently at- 

 tacked by this fly, and have, in general, a greater number of bots than 

 others : the strongest and healthiest beasts seem constantly to be pre- 

 ferred by it, and this is a criterion of goodness in much esteem among 

 dealers in cattle. 



The tanners also observe that their strongest and best hides have 



