162 FIRST ANNUAL REF0RT OF 



the little hooks or tentacula placed each side of the head, to the mem- 

 branes which line the cavities, feeding on the mucus which is always 

 to be found in them. Until they attain their growth they are of a 

 creamy white color, with two brown spots placed side by side on the 

 posterior segment. These spots, (6, c) are spiracles or stigmata, through 

 which the worm breathes. The segment with these two spiracles, 

 is retractile, and can be drawn in and hidden at the worms pleasure. 

 When full grown, the grub becomes darker, particularly towards the 

 tail, the white of the first two or three segments becomingdirty white 

 on the 4th or 5th, and growing darker on each successive segment 

 until the last, which is of a very deep brown. It has two small paral- 

 lel hooks or tentacula at the head (a), and above these, two very 

 small tubercles, not very easily shown in the engraving. It also has 

 a small brown elevated round spot on each segment along the sides, 

 which might at first be taken for spiracles but which are not, and 

 also two small corneous appendages (5, b) on each side of the anus. 

 The ventral region has a band of small elevated dots running the 

 breadth of each segment in their middle, which, under the magnifier 

 appear to be minute brown spines, all pointing posteriorly. (See Fig. 

 91, 5). These aid the worm in its movements. 



When ready to contract into a pupa, it descends down the nostrils 

 of the sheep and falls to the ground, where it quickly buries itself 

 and in about 48 hours, contracts to half its former size, and becomes 

 smooth and hard and of a black color, tapering as in the larva to- 

 wards the head. It remains in this state from 40 to 50 days, or more, 

 according to the weather, when the fly pushes open a little round cap- 

 piece at the head and thus arrives at maturity. 



In this stage it looks something like an overgrown house-fly. 

 The ground color of the upper part of the head and thorax is dull- 

 yellow, but they are so covered with little round elevated black spots 

 and atoms (scarcely distinguishable without the aid of a magnifier) 

 that they have a brown appearance. The abdomen consists of 5 rings, 

 is velvety and variegated with dark brown and straw color. On the 

 under side it is of the same color, but not variegated in the same way, 

 there being a dark spot in the middle of each ring. The feet are 

 brown. The under side of the head is puffed out, and white. The 

 antenre are extremely small and spring from two lobes which are 

 sunk into a cavity at the anterior and under part of the head. The 

 eyes are purplish brown, and three small eyelets are distinctly visible 

 on the top of the head. It has no mouth and cannot therefore take 

 any nourishment. The wings are transparent and extend beyond the 

 body, and the winglets, which are quite large and white, cover en- 

 tirely the poisers. Its only instinct seems to be the continuation of 

 its kind. It is quite lazy, and except when attempting to deposit its 

 young, its wings are seldom used. 



It has lately become the fashion with many members of the Agri- 

 cultural press, to ridicule the idea that sheep die at all from grub in 



