DISSECTION OF TICKS 653 



down by muscles, tracheae, strands of connective tissue, etc. All 

 these structures should be detached close to the under surface of the 

 dorsal integument with the aid of the needle. Special care should be 

 taken not to damage the heart and aorta ; the former may be seen lying on 

 the mid-intestine. When the dorsal integument has been completely 

 reflected several pins are passed through the sides of the ventral skin in 

 order to prevent it from curling up. All the remaining manipulations 

 can be carried out with a needle and a pair of forceps. A glass pipette 

 with a rubber teat should be kept ready for use, as it is often necessary to 

 flood some particular part which has become obscured by the dark fluid 

 from a ruptured intestinal diverticulum. Care should be taken to see 

 that the needles have clean points, for if they are rusty the organs tend 

 to stick to them. 



In dealing with male ticks care must be taken not to rupture the 

 delicate sexual organs ; the tick should be held by the mandibles and 

 hypostome with a pair of broad flat forceps while the initial cut is 

 made. Most nymphs can be dissected in the same way as the adults, 

 but instead of attempting to cut right round the margin only a small nick 

 is made with the scissors, and the incision continued with sharp needles 

 after pinning the specimen in the trough. There is no really satisfactory 

 way of dissecting the larvae. Most of the internal organs can be pushed 

 out through a small incision at the posterior end, the manoeuvre being 

 carried out in a drop of saline on a slide. The relations of the parts in 

 the larva can only be studied in serial sections. 



When the dorsal integument has been removed and all the connective 

 tissue, etc., cleared away, the intestinal diverticula are hooked up 

 with a bent needle and then slowly unravelled. They float up in the 

 saline and can be pinned to one or other side. The salivary glands will 

 now be seen stretching back from the mouth parts to the neighbour- 

 hood of leg IV. They will be recognized by their lobulated appearance 

 and white colour. The salivary duct may be followed up to its termina- 

 tion in the floor of the buccal cavity. The anterior end of the mid-gut 

 should now be lifted up and the delicate oesophagus exposed ; it will 

 be seen passing downwards from the ventral surface of the anterior 

 end of the mid-intestine towards a large rectangular white organ, the 

 brain, through which it passes ; it emerges again at the anterior end of the 

 brain to enter the pharynx or pumping organ. This latter structure will 

 be found lying on the ventral side of the basis capituli between the two 

 mandibles. On lifting up the posterior end of the mid-intestine and 

 turning it to one side the hind-intestine will be exposed ; in most cases 



