MEMOIR OF LATREILLE. 
31 
being of insects, is still merely artificial, that it is not 
sufficiently strict, for the order of the Suctoria is an 
apterous group, not in its right place among the 
Insecta Pterodicera. And also the groups which 
are here considered as equivalent to the Tetracera, 
Myriapoda , A pterodicera , and Pterodicera, are hy no 
means of equal value, hut the two first and two last 
are most closely allied ; the former are the subordi- 
nate members of a higher group, and the latter also 
could at most he placed as equivalent to the orders 
of the Insecta pterodicera” 
Before leaving this subject, it may he desirable to 
show briefly, in juxta-position with the above, somo 
of the various changes our author afterwards made in 
his arrangement, for in every successive work im- 
portant alterations were effected. In his “ Conside- 
rations generates sur l’Ordre Naturel des Animaux 
composant les Classes des Crustaces, des Aracliuidcs, 
et des Insectes," * the Linnean Insecta was divided 
into three equivalent groups, Crustacea, Arachnides 
(including the Insecta aptera of the former system), 
and Insecta. Such was likewise the arrangement 
which appeared in Cuvier’s Regne Animal t, but 
the groups were differently defined, and some of the 
contents ot eacli transferred to another. There was 
likewise the necessary addition of the order Strep- 
siptera, recently discovered by Kirby. After seve- 
ral other changes, of more or less importance, in 
different works, we come to that embodying his 
latest views, published in his “ Cours d’Entomo- 
logie,”J which was completed onlya short time before 
* Paris, 1 BIO, 8vo. t Paris, 1817. J Paris, 1832, 8vo. 
