104 
THE entomologist's RECORD. 
the last few weeks, in newly emerged specimens of Arctia lubricipeda^ 
A. ?nenthastri, Smerinthus ocellaius^ Limacodes iestudo, etc. During 
expansion, pricking the membrane at any portion of the wing results in 
the exudation of a drop of fluid. This fluid disappears rapidly when 
expansion is completed, and dries from the base. When saccular dis- 
tension takes place, the mere fact of killing the insect and leaving it to 
dry does away with the distension, the fluid evaporating, but in this 
case the membranes, previously stretched by the excess fluid, contract 
and dry irregularly. If the exudation of the insect had any connection 
with the fluid by which expansion is brought about, it would be difficult 
to explain why newly emerged insects, if touched or pressed will exude 
first, and the wings afterwards expand quite normally. — J. W. Tutt. 
July, 1891. 
Generic Nomenclature and the Acronyctid^. — With reference 
to Mr. Tutt’s remarks in the June part of the Entomologisf s Record, I 
may say that the whole question of entomological nomenclature is 
extremely difficult and complicated, and cases continually arise which 
can hardly be decided by any existing rules. Some of these, but by 
no means all, are considered in the preface to my Catalogue of Neuro- 
ptera Odonata. The number of generic names of insects (some in 
current use, others ignored, some characterised more or less completely, 
and others not at all) is so vast that I think it most desirable to avoid 
adding to the mass unnecessarily. Hence I would never rename a 
genus for which any existing name, characterised or otherwise, is 
available. To quote from my preface (p. v.) : — “ The limits of a genus 
are always variable, and its characters subject- to modification, both 
according to the increase of our knowledge, and to the divergent views 
of different entomologists ; hence, although no generic name ought to be 
issued without a description, yet the fixing of a type, which must always 
be an identifiable species placed in it when the generic name is used for 
the first time [and one which does not contradict the characters of the 
genus, if any are given, or the meaning of the generic name, if it has 
any] appears to be even more important, for no real certainty can be 
obtained without. In fact the fixing of the type of a genus is to the 
description what the figure of an insect is to the description of a 
species.” Hiibner was far in advance of his age, and perceived that a 
much more minute subdivision of species was necessary than other 
entomologists were willing to admit for fifty years afterwards, and he 
tried various experiments in nomenclature with more or less success. 
It was natural enough for Boisduval, in whose time 20 or 30 of Hiibner’s 
“Coitus” (as the latter called subdivisions corresponding to our modern 
genera) were regarded as one homogeneous genus, to reject Hiibner’s 
work on principle ; but we cannot do so now, when we subdivide genera 
to the same extent as Hiibner, only that we subdivide them differently, 
according to what we consider, with our present increased knowledge, 
to be more important characters. If every author who alters or improves 
the characters of a genus considers himself at liberty to rename it, or to 
impose a new name on any subdivision of a genus, without inquiring 
whether any name exists which can lawfully be applied to it, we may as 
well abandon the study of entomology as foredoomed to hopeless and 
irretrievable confusion. 
I have not yet sifted the nomenclature of the Acronyctidce ; but I 
