MODE OF DISSECTING INSECTS. 291 



each side of the back with fine scissors, the dorsal por- 

 tion of the integument can be carefully removed so as to 

 leave the inner cellular layer (hypodermis) untouched; this 

 should then be raised, disclosing the delicate tubular dorsal 

 vessel or heart. Below it lies the alimentary canal,, which 

 passes through the middle of the body. The nervous sys- 

 tem can be seen upon removing the alimentary canal, as it 

 lies loosely on the floor of the body; but in order to work 

 out the ganglia in the head, it is better at first, with a 

 sharp, thin scalpel, to cut a well-hardened locust in two 

 longitudinally, the section passing through the brain and 

 subcesophageal ganglion. Indeed, a "sagittal" or longitu- 

 dinal section of a well-hardened locust or grasshopper can 

 be easily made, and when floated out in a shallow pan of 

 water and examined with a Coddington lens attached to the 

 movable arm of the lens-holder can be studied and then 

 put away in a wide-mouthed bottle for future observations. 

 Mr. Frank Cheshire has in his work on the honey-bee 

 given some useful hints on the dissection of that insect. In 

 order to dissect the salivary glands of a worker-bee, he 

 adopted the following method: 



" By inserting a needle into the mouth of a worker-bee, and pass- 

 ing it upwards, behind the front wall of the head, the latter may be 

 so opened that its salivary (?) glands, in a partly broken condition, 

 may be obtained for examination; but if the attachments and entire 

 forms are to be investigated, we must proceed as follows: Partly till 

 some shallow receptacle, such as a pomatum-pot, or large pill-box, 

 with melted bee's or paraftine wax. When cold, with a hot wire melt 

 a little bath in the centre of the waxen surface, and then insert the 

 bee we wish to dissect, so placing in this case that one side of the 

 head is submerged. By a second application of the wire, re-melt the 

 wax in the neighborhood of the head, using no more heat than is 

 necessary to secure thorough adhesion, and now cover with water or 

 glycerine. A powerful light and a good watch-maker's eye-glass 

 (secured round the operator's head with a tape, when it can be pushed 

 up on to the forehead if not required) will permit of reasonably good 

 dissection, although, of course, better results can be reached by using 

 a Stephenson's erecting binocular microscope the instrument with 

 which all the dissections for this work have been made. The bee 

 thus securely held by the wax, both hands are free to manipulate. 

 Now, with a needle-knife (made by heating a large needle, beating it 

 flat, and afterwards sharpening upon a hone, and inserting into a 

 wooden handle) cut carefully round the compound eye, and lift it 



