Limbs and Mouth-parts of Crustaceans and Insects. 431 
higher Collembola the hypopharynx is of large size and the 
maxillule have only an inner and an outer lobe (“ para- 
glosse’’ and palpus). Stummer-Traunfels furnishes us 
with a good résumé of the extremely divergent interpretations 
of these parts by different authors, such as Meinert, Lubbock 
(who terms the ‘ paraglosse”’ the ‘second maxilla”’), and 
Tullberg (whose description is on the whole excellent and 
who possessed a keen eye for the difficulties in the interpre- 
tations given by the two previous writers). The maxillule 
are, as has been already stated, inserted before the maxille 
and behind the point of origin of the hypopharynx; they have 
nothing to do with the labium. 
40. Itappears to me that the facts detailed in §§ 28-32 and 
36-39, when taken together, show the great agreement that 
exists between the mouth-parts of the primitive Insects named 
and those of the Malacostracous Crustacea and that they 
render evident the homologies which I have set up. 
41. Lepisma stands, as regards the structure of the mouth- 
parts and the thoracic feet, between Machil’s and the Ortho- , 
ptera. 
42. Hemimerus talpoides, Walk.*, is a genuine Ortho- 
pteron, and in the structure of its mouth-parts approaches 
very near to Forficula. 
43. ORTHOPTERA.—The muscles of the mandibles, e. g. in 
Acridium, exhibit conditions which are very divergent from 
those found in the Thysanura. By comparison with Machilis 
(§ 29) and by a process similar to that adopted in the case of 
the Isopoda it may be shown that the maxille, e.g. in For- 
jicula, are composed of a first segment (cardo) without a lobe, 
a second (transversely divided) segment with the masticating- 
lobe, and a third (very obliquely cleft) segment with the galea, 
together with a palpus proceeding from the third segment ; 
the second and third segments with their four parts together 
constitute the “ stipes.” (In the interpretation of the boundary 
between the lobe and the segment in the case of the second 
and third segments I have here on practical grounds not 
followed the certainly more correct interpretation employed in 
the case of the Crustacea, according to which the basal 
division alone is termed the segment ; but the question has 
the less interest since it only turns upon the determination of 
the actual boundary between the segment and its lobe.) he 
hypopharynx is well developed; the maxillule are still 
present in various forms (e. g. Forficulide and larvee of 
Ephemeridz) as a lobe, which is attached to the skeleton at 
the base of the hypopharynx. 
* A paper of mine on this animal is nearly ready for the press. 
