Reports to the Board of Agriculture. 129 



about through the connective tissues of the host and between the 

 skin and flesh. They finally take up their position along the back, 

 just under the hide, and then moult again, when they become spiny. 

 At this stage they commence to produce considerable irritation, a 

 swelling arises over them — the '■ warble " — which soon becomes 

 perforated by a hole at the summit. The tail end is directed towards 

 this aperture, the two spiracles or breathing pores situated on it 

 being placed close to the opening. There is now formed much pus, 

 upon which, together with blood, the larva or bot feeds and rapidly 

 develops, and then moults for the last time. When mature the 

 yellowish-white bot turns greyish-brown with grey stripes, and is 

 about an inch in length, the body being very spiny. By means of 

 these spines the maggot makes its way out of the warble-cells and 

 falls to the giound. 



Tlie larva then enters the puparium stage (Fig. 22, d), which may 

 take place either in the ground or under some stone or foreign body 

 lying on the ground. 



This puparium is formed by the bot's old skin, which hardens 

 and gradually becomes almost black in colour. In from three to six 

 weeks the fly escapes from tliis case through a more or less circular 

 opening or cap in the puparium. 



The perfect insect is half an inch long, very hairy, black, clothed 

 with almost white, reddish-brown and black hairs ; there are white 

 hairs on the head and thorax, and forming a band at the base of the 

 abdomen. There are also blackish -brown hairs on the upper part 

 of the head, the thorax, the legs, and the middle region of the 

 abdomen. 



This fly appears in Great Britain from the middle of May until 

 the beginning of September. 



Life-history of H. hovk. 



The life-history of this s])ecies is not, I feel sure, properly known. 

 Probably it is the same as lincata. It is said to lay its eggs on or 

 in the skin, but there is no evidence to show this. According 

 to Miss Ormerod's notes it ap])ears that the bots develop directly 

 under the hide, appearing first as small blood-red maggots between 

 the hide and flesh. These grow into the mature l)ots and cause 

 warbles similar to the former species. 



The " bots " of bovis are easily told from those of lineata by the 

 two last segments of the body being free from spines, whilst in 

 lineata the last segment only is nude. The mature bot of lineata 



K 



