OF SUCTION IN LYGUS PABULINUS. 687 
generally cleared in turpineol, which did not make them brittle, 
even if they were kept in it for a long time. 
HoMo.LoGigEs oF THE MoutH-PArts oF RHYNCHOTA. 
The problem of the true homologies is very difficult, and has 
only recently been solved. In this section I propose to give a 
summary of the literature dealing with this problem. 
Fabricius gave the name “ Rhynchota” to the insects comprised 
in the class “‘ Hemiptera,” on account of their sucking mouth- 
parts. But till the time of Savigny (42), no attempt was made 
to homologise their mouth-parts with those of other (biting) 
insects. He hit upon the interpretation which is now generally 
accepted, According to him, the mouth-parts of the Rhynchota 
are homologous with those of the biting insects; the maxille, 
the mandibles, and the labium being represented in these forms 
by the internal stylets, the external stylets, and the proboscis, 
respectively. His interpretation has been endorsed by Kirby 
and Spence, Burmeister, and lately by Heymons and Leon. 
Savigny and Cuvier, one with Wepa cinerea, and the other 
with Ranatra linearis, had found the labial palps articulated to 
the proboscis. But they could not discover any trace of the 
maxillary palps, which are well-developed structures in the biting 
insects. They had not, therefore, good evidence for the homologies 
of the maxille. 
These matters will be better elucidated if the history of the 
homologies of each part be treated separately. 
The Proboscis, or Schnabelscheide. 
There were two views with regard to the structure of the 
proboscis before 1880 :— 
(i.) Burmeister (5), Latreille, and Graber held that the proboscis 
was formed by the second maxille fusing together with the labial 
palps. Burmeister has stated this view in very general and 
vague terms, but it was Kraepelin (25, 26) who elaborated it in 
detail. According to him the first segment of the proboscis 
corresponds to the submentum and mentum together, and the 
three segments, 2, 3, 4, to the three segments of the labial palps 
of the biting insects. This view had been supported by the fact 
that there were, on the second joint of the proboscis, certain 
strong chitinous tubercles which were supposed by him to be 
the rudiments of the organs, 7. e. extremities of external and 
internal lobes of the palps. Leon (30), however, takes them 
to be the -chitinous supports for the muscles of the proboscis, 
running into the head. 
This view has been exploded, and no present-day writers think 
seriously of it, its interest being now purely historical. 
(ii.) The second view was first formulated by Savigny and 
Cuvier, and is now generally accepted. Savigny, in Vepa cinerea, 
and Cuvier, in Ranatra linearis, discovered certain jointed 
