ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
337 
elements, and of ordinary protoplasm in which these elements are 
imbedded, the so-called sarcoglia, sarcoplasm, and intermediate substance. 
The contractile elements are plasmatic columns or plates set in longi- 
tudinal rows in the muscle-cell ; they are rounded or flattened in form. 
The sarcoplasm is plexiform, and generally irregularly so ; it stains 
with difficulty. The nuclei imbedded in it vary in number, form, and 
size ; they sometimes lie directly on the surface of the muscle-cell, 
and sometimes within it. The outermost layer of the sarcoplasmic 
network which forms the surface of the cell, exhibits a so-called alveolar 
layer ; it is capable of being more deeply stained than the rest, and its 
higher refractive power gives rise to the so-called pellicula. This last 
may correspond to the sarcolemma of earlier authors. 
The wing-muscles of all the Insects examined exhibit a still further 
complication. Spherical corpuscles are imbedded in the network ; they 
vary greatly in form and size. In living muscle- cells they appear to be 
homogeneous, and are highly refractive ; when fixed they have a fine 
plexiform structure, and stain almost as deeply as the muscle-nuclei. 
The finer structure of the contractile elements is also plexiform and 
complicated. The characteristic peculiarity of transversely striated 
muscle cells is the differentiation in a longitudinal direction of the 
framework of the contractile elements. 
Comparing the results of the present writers with those of their 
predecessors it may be said that the “ primary disc ” corresponds to their 
two transverse rows of the anisotropic portion, while the two “ isotropic 
discs ” correspond to their two transverse rows of the isotropic portion ; 
the “ intermediate disc ” is the boundary between two transverse rows of 
this portion, and the two “ secondary discs ” are the boundary-lines 
between every two opposed rows of anisotropic and isotropic parts. The 
transversely striated muscles of Vertebrates appear to have essentially 
the same structure as those of Crustacea. 
a. Insecta. 
Food of the Larvae of Insects.* — Dr. D. Levi-Morenos has studied 
the contents of the intestinal canal of larvae found in the marshes of the 
Piave, near Belluno. The larvae belonged to the family of Culicidae, 
to Chironomus yplumosus or some allied species. The conclusion arrived at 
was that the food of these larvae consisted almost entirely of diatoms 
belonging to the genera Cymbella, Geratoneis , Odontidium , Meridion , 
Navicula , &c. This is contrary to the view of Lefevre, who describes 
the larva of this species as carnivorous. The author points, out the 
importance of this question in relation to pisciculture. 
Odoriferous Organs of Lepidoptera.j — Dr. E. Haase has studied the 
odoriferous organs in Indo-Australian Lepidoptera, and of his results 
F. Plateau gives a terse analysis. The odoriferous organs are either 
defensively repellent, as in some Danaids, or sexually attractive. In 
some Bombycidae, as is well known, the females attract the males from 
long distances ; in most cases the odour of the males is attractive to the 
females. 
Some of the odoriferous scales occur on the wings. There they are 
* Neptunia, i. (1891) pp. 7-11. 
t Bull. Soc Entomol. Ital., xxii. (1891) pp. 138-43. 
