ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 201 
some interesting variability : — Thus the place of rupture may be different 
in the same species ( Timarcha ); some individuals do not show any 
bleeding ; it seems to occur in specimens of Melasoma at Halle, but not 
in those of France. 
Labium of Hemiptera.* — Dr. N. Leon confirms what he discovered 
in 1887 and in 1892, that the Hemiptera have not only labial palps, but 
also rudiments of the external and internal lobes. He has investigated 
Benacus griseus Say, ZaitJici anura , Gerris Najas, Velia rivulorum , &c., 
and maintains the complete homology between the labium of Hemiptera 
and that of biting insects. The first joint corresponds to submentum and 
cardines, the second to mentum and stipites ; the third and fourth joints 
represent paraglossae or ligulae, or, more probably, both united. 
Evolution of Lepidoptera.f — Dr. Grafin Maria von Linden discusses 
Prof. Eimer’s work on the origin of species in Lepidoptera, and especi- 
ally of the lines of evolution disclosed by a study of the markings. “ It 
has been shown,” she says, “ that a large number of changes in the 
individual animal arise from the operation of external influences, that 
these variations are similar to those observed in nature, and occur like- 
wise in definite directions. It is also shown that the variations which 
arise by organic growth are transmitted to descendants, and that the 
different stages of variation which are exhibited in the phylogeny as 
specific characters are recapitulated as transient stages in the ontogeny.” 
“ If Prof. Eimer’s claims are correct,” says Minot, “ his researches mark 
one of the great epochs of biological discovery.” 
Growth of Silkworms4 — Sigg. Luciani and Lo Monaco have inves- 
tigated the progressive increase in the weight and nitrogenous content 
of silkworms, considered in relation to the nutrition at successive stages. 
Unusual Case of Myiasis.§ — Dr. G. Alexandrini reports an unusual 
case of myiasis due to the larvae of Sarcophaga carnaria Meig. in the 
nasal cavity of man. After describing the case and the treatment, he 
notes some similar occurrences. 
Larva of Thrixion Halidayanum.|| — M. J. Pan tel describes some of 
the structural peculiarities of this Dipterous larva. The gut is sim- 
plified in adaptation to parasitism ; thus the oesophagus and the hind-gut 
■are short, the stomach and gastric appendages are suppressed, and the 
place of the proventriculus is taken by a hard cushion (with associated 
musculature) on the upper wall of the oesophagus. The heart— a mus- 
cular tube closed behind — is also described. More interesting, perhaps, 
is a metameric organ in the seven abdominal segments. It is formed in 
-each side of a somite by a twin group of giant-cells, and possibly repre- 
sents a closed excretory organ. 
Notes on Strepsiptera.H — Prof. N. Nassonow criticises Prof. F. 
Meinert’s recent denial of the existence of a cephalothorax in Strepsiptera, 
.and his identification of the cephalothorax as the posterior end. The 
* Zool. Anzeig., xx. (1897) pp. 73-7 (5 figs.). 
t Biol. Centralbl., xvii. (1897) pp. 179-90, 213-2G. 
X Atti (Rend.) R. Accad. Lincei, vi. (1897) pp. 155-32. 
§ Boll. Soc. Rom. Stud. Zool., v. (1896) pp. 191-7. 
II Comptes Rendus, exxiv. (1897) pp. 580-2. 
1 Zool. Anzeig., xx. (1897) pp. 65-6. 
1897 
p 
