40 



the ventral side and just behind the genital orifice. The sexes resemble 

 each other, but may be separated by their size and by the form of the 

 external genital apparatus. 



In habit these parasites resemble lice living among the hairs of the 

 fleece, whence the name, louse-fly. They seldom remain attached to the 

 skin longer than a sufficient time to fill up with blood ; this they suck up 

 through the proboscis with which they perforate the skin. They try to 

 evade capture by running into the wool, and when caught cling tena- 

 ciously. 



Life history. — The family of flies to which this parasite belongs is 

 truly wonderful, in that tliey bring forth their young as puparia. The 

 puparia of JlFelophagus are laid as flat, ovoid, chestnut brown, glistening 

 seed-like eggs, which are nearly one-third as large as the abdomen of 

 the parent, and contain an imperfectly developed larva within them. 

 The egg cases or pupa are marked by two rows of seven dots each on 

 one surface, a slight depression, indented by two dots in one end, and a 

 slight elevation at the other. The two dots are at the anal end. A 

 dissection of one of these, taken from a female, shows the poin.ted end 

 to be connected with a membrane, and to be the end through which the 

 larva obtains food. 



Some authorities say that each female produces but one or two of 

 these i)uparia ; others say that they can lay about eight or nine during 

 their life-time. They lay one at a time in the wool. A portion of each 

 puparium will be found to be covered with a dry, dark substance, which 

 came from the parent when the puparium was laid, was sticky, and glued 

 it to the surrounding hairs. This prevents the pupa, which becomes 

 hard, dry, and glassy, falling from the wool. The insect emerge, 

 with adult characters from the pupjie cases, through an opening in the 

 end of the case made by a round lid splitting ofl", and wanders into the 

 wool. Some of these eggs collected in the course of our investigations 

 hatched within four weeks at ordinary temperatures. 



Occurrence. — These ticks, or their young, may be found on the sheep 

 at all times of the year, but appear to be most numerous in spring. 

 They are particularly noticeable at shearing time on the old sheep after 

 they are deprived of their shelter. At this time those that can .do so 

 take refuge in the longer wool of the lambs, and prove veritable pests. 

 The others perish either from being eaten by the sheep, carried a^vay in 

 the wool, or dropped to the ground. They frequently become attached 

 to the clothing and persons of people with whom they come in contact, 

 but they prove but a slight source of discomfort, as they are easily 

 caught and killed. It is not at all probable that they can exist many 

 days apart from the sheep, as they are unfitted by structure for any 

 other habitat. Their food consists wholly of the blood which they suck 

 from the sheep. They depend also on the sheep for warmth ; in warm 

 spring days they may be found crawling near the ends of the wool, 

 while in the colder days they will always be found either engaged in 



