402 ON INSECT ANATOMY. 



of base of cranium with maxilla and palpi, gula, labium, lingula, 

 paraglossoe, &c. The study of such sections of the dermo-skeleton, 

 from which the soft parts are removed by boiling in solution of 

 potash, is a necessary preliminary to the study of the very intricate 

 anatomy of the soft parts contained within them, e.g.^ Tongue, 

 pharynx, sesophagiis with its salivary glands and muscles, supra 

 and infra-8esophageal ganglia and nerves, together with a mass of 

 intra-cranial muscles arising from the inner surface of the cranium 

 and internal processes, and attached to sesophagus, palate, and 

 mandibles. 



The student will be greatly assisted, and valuable time saved, by 

 purchasing all good insect preparations which he can obtain 

 commercially. Such preparations will probably be far better made 

 and mounted than those which he makes for himself. Eut no 

 cabinet of preparations wiU teach that knowledge of insect anatomy, 

 which is to be gained only from actual dissection. The relation of 

 the soft parts to the dermo- skeleton, and their own relative position 

 to each other, can only be learnt in their entirety by those who 

 dissect them in the fresh state and examine them in situ. Besides 

 which, preparations of the most important and interesting parts are 

 not usually made for sale, as they are difficult to dissect, and demand 

 much time in preparing. But whilst dissecting for himself, the 

 student will find every tissue and fragment of tissue well worthy of 

 study from histiologic points of view, as well as on account of their 

 anatomical relations. Tor instance, it is always well to examine 

 fragments of muscle fibre scattered in the field, for the chance of 

 securing good examples of nerve insertion under the sheath of the 

 muscle, and distribution of its terminal filaments in the muscle 

 substance. Fragments of gland structure sometimes ofi'er unex- 

 pected yet beautiful specimens for preparation. The same may 

 happen with varieties of gland in mucous membrane of intestines 

 and other organs (testis, urinary tubes, hepatic tubes, «&c.). 

 Beautiful varieties of fatty tissue and dermoid tissues or exquisitely 

 striated muscle (as in the coats of the dorsal vessel) or curious forms 

 of tracheal ramification and wonderful networks distributed over or 



