432 Dr. H. J. Hansen on the Morphology of the 
44, CoLEOPTERA.—The mandibles, maxille, and labium 
agree with the utmost exactness with those of the Orthoptera 
in structure and relative position. A difference arises in 
consequence of the fact that the hypopharynx is either so 
much reduced in size as to disappear, or, as seems to me more 
probable, has become firmly attached to the inner side of the 
labium, which on the whole becomes pressed upwards against 
the underside of the head more closely than in the case of 
Orthoptera; many peculiarities (e. g. in Melolontha) point to 
the probability of the latter explanation. The maxillule are 
entirely wanting. 
45. The hypopharynx is a freely projecting organ only in 
the Thysanura, Orthoptera, and Diptera; apparently we also 
find it in the Rhynchota as a short free point (Wedde, and 
my own observation in Nepa). It is often termed “ tongue,” 
which may well be admissible, but is not very happy. On 
the other hand, many authors frequently employ the term 
“tongue” in a very arbitrary and objectionable manner for 
portions of the labium ; “ paraglosse,” a term which should 
be entirely rejected, is used sometimes for portions of the 
labium, and at others for parts of the maxillule. 
46. The antenne in Insects are sometimes regarded as 
homologous with the antennules and sometimes as homologous 
with the antenne in Crustaceans. As an argument in favour 
of the former supposition we have the fact that the antenne 
of Insects, as also the antennules of Crustaceans, are inner- 
vated from the deuterocerebrum (Viallanes); the second 
theory is supported by two reasons. As has been demon- 
strated with respect to both classes by a series of authors, the 
rudiments of the antenne are postoral in position both in 
Insects and in Crustaceans ; it is true that a single author has 
stated the same thing with reference to the antennule, but 
this is certainly very much open to doubt. In the terrestrial 
Amphipods (Orchestia) the first pair of antenne, the an- 
tennules, have become very short, and in the most charac- 
teristic land-Isopods (Armadillidium, Armadillo, Tylos, 
Syspastus) they have become extraordinarily small and are 
reduced even to the point of disappearance, while the second 
pair of antenne are well developed. 
47. Upon the mandibles of certain Coleoptera and larvee of 
several species of Ephemeridz I have found a well-developed 
Jacinia mobilis. 
48. How far the embryonic provisional lobes which have 
been found by different authors in several of the higher orders 
of Insects (and with respect to which Korschelt and Heider 
write on p. 793 of their text-book: “ ‘This lower-lip-forma- 
