The Elements of Insect Anatomy Author:John Henry Comstock, Vernon L Kellogg Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: CHAPTER III. THE INTERNAL ANATOMY OF AN INSECT. Corydalis cornuta. The larva of Corydalis cornuta lives under stones in the bed of swiftly flowing streams... more » ; it is well known to sportsmen under the name of " dobson," and is used extensively as bait for black bass. As the larval state of Corydalis lasts nearly three years, larvae which are at least two years old may be found at any time. They are most abundant where the water flows swiftest. A good way to obtain them is to hold a dip-net or a wire screen in the stream below some stones, and, lifting the stones with a hoe or garden rake, cause the current to sweep into the net the insects which were under the stones. This larva is probably as desirable a subject for an elementary study of the internal anatomy of insects as can be found in this country. The species is a large one, being one of our largest insects ; there is a coarseness in its structure, which enables one to study the different viscera with comparative ease ; it is furnished with well-developed organs for aquatic respiration, and at the same time with equally well- developed organs for aerial respiration; and, as already stated, fresh specimens can be easily obtained at any season, even in mid-winter. Unfortunately, however, the appearance of the insect is very disagreeable to most people. But after a specimen has been opened and pinned upon cork, as is necessary in the study of the viscera, the disagreeable features are not visible ;and the ease with which the internal organs can be examined more than counterbalances the unpleasant part of the preparation of specimens. PRESERVATION OF SPECIMENS. Specimens that are to be used for the study of internal anatomy should be preserved in an aqueous solution of chloral hydrate ; this is made by dissolvi...« less