摘 要：
In this paper, the types of insect metamorphosis are discussed and a new system of insectclassification is proposed. Of insect metamorphosis, three primary types are recognized: 1. Anamorphosis——Protura, 2. Oligomorphosis——Collembola, 3. Epimorphosis——Diplura,Thysanura,Pterygota. These three types differ from each other in the development of body segments: in the Ana-morpha, the young larva leaves the egg with a small number of postcephalic segments, and post-embryonic growth is characterzed by an increase in the number of abdominal segments; in theEpimorpha, the young larva, at the time of eclosion, has already been in a state with completebody segments and consequently, there is no increase in segmentation during post-embryonic growth;the Oligomorpha are like the Anamorpha in having oligomerous larvae, but they resemble, on theother hand, the Epimorpha in the fact that the body segments do not increase during the succeed-ing period of development. Anamorphosis is regarded the most primitive type of development from which both oligomor-phic and epimorphic types were derived. Oligomorphosis is a type of precocious development orneoteny (Imms, 1936) very characteristic of Collembola, and there are at least three important larvalfeatures which are evidently retained in the adult stage of these insects, i. e. the six-segmentedabdomen, the four to six-segmented antennae and the larval character in the structure of the gonads.The last mentioned structure has been particularly stressed by Tiegs (1945) who, in discussing thereproductive organs of larval Symphyla, said: "Unless the facts are quite misleading we have inthe ovary of Collembola, an organ which is the almost perfect equivalent of the ovary of thelarval Symphyla." The epimorphotic mode of development is again divisible into four types: 1. Eometamorphosis——Diplura, 2. Prometamorphosis——Thysanura, Ephemerida, 3. Hemimetamorphosis——Exopterygota less Ephemerida, 4. Holometamorphosis——Endopterygota. The Eometabola and Prometabola are characterized in their post-embryonic growth by two verydistinctive features: 1, they continue to moult in the adult stage, either once or more times; 2. theypossess two types of larvae, the young larvae without abdominal appendages (fig. 2 A) and theold larvae with abdominal styli (fig. 2 B). The Eometabola are further distinguished by the pre-sence of a quiescent first instar (fig. 3) or "pupoid stage", which, as Smith (1961) pointed out,has been also described by various authors for the classes Pauropoda, Diplopoda, Chilopoda, andfor the order Collembola. This instar is absent, however,in the Symphyla, Thysanura and Ptery-gota. It represents, therefore, a primitive feature of development and eometamorphosis, as a dis-tinct type of metamorphosis, should be considered as more primitive than prometamorphosis inwhich the "pupoid stage" is no longer retained. The classification of the modes of post-embryonic development discussed above agrees in mainline with the general system of insect classification. As recent studies of insect phylogeny have shown:1. the Collembola and Protura are isolated groups rather remote from the line of true insects,they exhibit many important myriapodous characters and may be considered as semi-myriapoda ormyriapoda-insecta; 2. the Diplura are also myriapodous in character from many points of view,but they are distinctly related to the true insects on the one hand and to the Symphyla on theother; 3. the Ephemerida constitute a primitive group very distinct from the other existing groupsof Pterygota. Hence the evolutionary history of insects would have passed through the followingprincipal stages: True Myriapoda→Myriapoda-Insecta→True Insecta (apterous)→Winged Prometabola→Hemimetabola→Holometabola. In a previous paper (Chen, 1958), we have proposed a classification of insects into three sub-classes: 1. subclass Myrientoma, comprising the orders Collembola, Protura and Diplura whichrepresent the Myriapoda-Insecta stage of evolution; 2. subclass Apterentoma, comprising the ordersMachilodea and Thysan
