It is a pleasant duty to offer our thanks for friendly help received. Professor Félix Plateau, of Ghent; Mr. Joseph Nusbaum, of Warsaw; and Mr. S. H. Scudder, of Cambridge, Massachusetts, have very kindly consented to treat here of those parts of the subject which they have specially illustrated by their own labours.[2] Mr. E. T. Newton, of the Jermyn Street Museum, has lent us the wood blocks used to illustrate one of his papers on the Brain of the Cockroach. A number of the figures have been very carefully and faithfully drawn for us by Miss Beatrice Boyle, a student in the Yorkshire College. We are much indebted to Dr. Murie, the Librarian of the Linnean Society, for procuring us access to the extensive literature of Insect Anatomy, and for answering not a few troublesome questions. [2] Prof. Plateau’s chief communications will be found on pp. 131 and 159; Mr. Nusbaum has furnished the account of the Development of the Cockroach, pp. 180 to 195; and Mr. Scudder the Geological History of the Cockroach, chap. xi. Five articles on the Cockroach were contributed by us to Science Gossip in 1884, and some of the figures were then engraved and published. In issuing a book which has been long in hand, but which can never hope to be complete, we venture to adopt the words already used by Leydig concerning his Lehrbuch der Histologie:--“Die eigentlich nie fertig wird, die man aber für fertig erklären muss, wenn man nach Zeit und Umständen das Möglichste gethan hat.” CONTENTS. CHAP. PAGE I.--WRITINGS ON INSECT ANATOMY 1 II.--THE ZOOLOGICAL POSITION OF THE COCKROACH 9 III.--THE NATURAL HISTORY OF THE COCKROACH 17 IV.--THE OUTER SKELETON 28 V.--THE MUSCLES; THE FAT-BODY AND CŒLOM 71 VI.--THE NERVOUS SYSTEM AND SENSE ORGANS 86 VII.--THE ALIMENTARY CANAL AND ITS APPENDAGES 113 VIII.--THE ORGANS OF CIRCULATION AND RESPIRATION (including a section on the Respiratory Movements of Insects, by Prof. Félix Plateau, of Ghent) 133 IX.--REPRODUCTION 167 X.--DEVELOPMENT (including a section on the Embryonic Development of the Cockroach, by Joseph Nusbaum, of Warsaw) 181 XI.--THE COCKROACH OF THE PAST, by S. H. Scudder, of the U.S. Geological Survey 205 APPENDIX:-- PARASITES OF THE COCKROACH. SENSE OF SMELL IN INSECTS. ⁂ Where the species is not named, it is to be understood that the figures are drawn from the Cockroach. LEEDS: MCCORQUODALE & CO. LIMITED, BASINGHALL STREET.