FARMERS' INSTITUTES. 167 



ou the abdomen, and Avith unclouded -svings. The GasfropJiilus pecorum is more 

 yello-\v, while the Gasfrophilus Juenioi'rhoidalis is easily distinguished by the 

 bright reddish tip of its abdomen. The larvre and pupfe of these species are 

 much the same iu habits and appearance as those already described. 



Sheep Bot-FJy. — CEstris oris, C'larlc. 

 This insect, while on mischief bent, is usually referred to by sheep raisers as 

 ''grub iu the head." It would be more proper to say maggot iu the head, as 

 the word grub is more usually applied to the larva? of beetles. 



Xatural History. 



The sheep gad-fly (Fig. 4), like that of the horse, appears from June till Sep- 

 tember. It is about the same form, too, as the Gasirophilus equi, and 

 when at rest or on the wing, is quite like our smaller horse-flies in 

 appearance. The color is light ash, dotted and lined with black. The 

 eyes are dark, and above and between these are three simple eyes. The fe- 

 sheep gari or ^^''^^G' after mating sccks to deposit her young — for these are ovovivipo- 

 bot-fly. rous, the eggs hatching within the mother-fly — about the nose of the sheep, 

 the only labor that is given them to do. They cannot take food even, as the 

 poor things are entirely mouthless. I say poor things, for as they have some 

 hundreds of young to provide with positions, it would be safe to conclude that 

 a lunch at least would not come amiss. The sheep receive these attentions with 

 no less worry and distress than that manifested by the horse on similar occa- 

 sions. They show their fear and annoya::cc by their bowed head, by shaking 

 the same and stamping their feet, and often by flight. 



The bots (Fig. 5), by means of their hooks and spines, pass up the nose, caus- 

 ing by their irritation an increased flow of mucus, on which 

 they feed. They may even reach the sinuses of the frontal and 

 maxillary bones, and in some cases the brain. When full grown j^j^ ^^ 



the maggots are an inch iu length. On the dorsal surface of sheep-bot. 

 each ring are two brown dashes, on the sides are raised spots of the same color, 

 while the general color is whitish. The rows of spines are very minute, point 

 back, and are only on the ventral surface of the rings. There are two hooks at 

 the mouth, above which are the same number of tubercles. The breathing- 

 l^ores are in the last segment. They are in small plates, and the entire seg- 

 ment can be retracted. When full grown they leave the nostrils, fall to the 

 earth, in which they at once assuyie the pupa state. 



The pupa condition lasts about two months, when the case becomes uncapped 

 and the fly issues. 



Effect Upion the Sheep. 

 Even such good authorities as Youatt and Clark deny that these bots do any 

 special harm. But there can be no question but that onr leading sheep men 

 are correct in the opinion that they do serious injury to the animal, and when 

 very numerous, especially if they pass to the brain, may, and frequently do, 

 cause death. The severe inflammation of the nasal membrane, reaching even to 

 the sinuses, together with the abundant discharge of purulent matter, gives 

 quick indication of a condition which no shepherd would desire. 



Sym2)toms. 



The sheep lose their appetite, shake their heads, seem inclined to butt, and 

 finally stupor and great weakness result. The mouth and nasal membranes 

 show great inflammation, while there is an unhealthy discharge from the nose. 



