ENTOMOLOGICAL NEWS, 



Philadelphia, Pa., November, 1919. 



The Use of the Term Larva. 



We have recently reread Professor Comstock's article in 

 the Annals of the Entomological Society of America for June, 

 1918, entitled "Nymphs, Naiads and Larvae." It will be re- 

 called that in it he proposes to limit the term nymph to the 

 early stages of insects which have a gradual metamorphosis, 

 as the Orthoptera and Hemiptera, and that naiad be used for 

 used for the immature stages of Plecoptera, Odonata and 

 Ephemerida ("incomplete metamorphosis"), while larva is to 

 be restricted to the young of insects with complete metamor- 

 phosis, Diptera, Lepidoptera et al., as some have already done. 



To us, however, this very narrow use of larva appears de- 

 cidedly objectionable, since the word has come to possess a 

 much wider significance, having been very generally employed, 

 in various languages, to denote the active, postembryonic stage 

 of many phyla which presents a more or less distinctly dififer- 

 ent aspect from the adult. Thus, Professor Edmond Perrier, 

 even after writing: 



The words larva and metamorphosis, borrowed from the vocabulary 

 of the entomologists, have indeed in Entomology a precise signification 

 from which one turns aside absolutely when one applies them to the 

 development of the Echinoderms, or to that of the Crustacea, or of 

 the great majority of worms. Metamorphosis is a more or less rapid 

 change, either in the internal organs or in the external forms, of an 

 organism already in possession of all the morphological units of 

 which its body is to be formed, 



goes on to add: 



Before the transformation, the animal is in the state of a larva, 

 after it in the perfect state. Such transformations can be observed 

 in numerous groups of the animal kingdom outside of the class of 

 Insects. One can consider as a metamorphosis the transformation of 

 Hphyra into a Discomedusa ; that of the vermiform larva of Coma- 

 tula into the cystidean larva ; that of the females of parasitic Copepods 

 into Lernaeans : that of cypris-larvae of Cirripedes into Anatifera, 

 Balanus or Sacculina; that of symmetrical into asymmetrical Pagtirus; 

 that of larvae of Bryozoa into protomerids ; that of three-segmented 



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