INTEODUOTION. 29 



until the year 1863 ; while, as regards England, I have 

 only met with the casual mention of two species, Podura 

 pinmhea and Smynthurus fuscus, in Samouelle's ' Ento- 

 mologist's Useful Compendium.' 



In the above-mentioned year I published my first 

 memoir on the Collembola, which was followed by a 

 second in the year following, a third in 1867, and a 

 fourth in 1869. In these memoirs I have recorded 

 about sixty English species, and have given some 

 account of their habits and anatomy. As regards the 

 latter, I differed in many important points from Nicolet, 

 to whom we were indebted for the first account of their 

 internal organisation. For instance, as regards the 

 digestive organs, I found myself compelled to question 

 the presence of Malpighian vessels. Again, with the 

 exception of Smynthurus, I found to my surprise that 

 the Collembola had no trachege, while Nicolet figured a 

 complete system of them in Fodura, and apparently 

 considered that a similar arrangement prevailed 

 throughout the group. 



These questions, however, are more fully considered 

 in the chapter devoted to anatomy. 



M. de Olfers, in his ' Annotationes ad anatomiam Po- 

 durarum, Dissertatio inauguralis,' adopted, for the 

 most part, the views of Nicolet. He was not, however, 

 acquainted with my memoirs. 



In 1865 Dr. F. Meinert,^ of Copenhagen, published 

 an excellent memoir on the Gam]3odece, which has been 

 translated in the ' Annals and Magazine of Natural 

 History' for November, 1867. 



Dr. Meinert incidentally mentions that he agrees 

 with me as to the respiratory organs of the Collembola, 

 but the principal part of the paper is devoted to the 

 consideration of the mouth parts. He points out that 

 the mouth of the Collembola differs from both of the 

 principal types found amongst insects. The mandibles 

 and maxillge do not articulate with the skull by means 

 of a hinge-joint, as in all other mandibulate insects, 

 1 " Naturliis. Tids.," 1865. ' Ann. Mag. of Nat. His.,' 1867. 



