ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
735 
displayed in the emergence of the moth, and of the moth itself at this time 
are only less remarkable than the possession of active jaws. Indeed, the 
author seems somewhat to doubt if the insect has been properly located 
in the system. 
Dicranota : a Carnivorous Tipulid Larva.* — Prof. L. C. Miall gives 
an account of the life-histoiy of Dicranota bimaculata , of which as yet 
nothing has been recorded. The larvas were plentiful on tho muddy 
banks of a little stream near Leeds, and they occasionally leave the 
water ; the pupal stage is passed in damp earth, and the pupa creeps 
to the surface shortly before the time for the emergence of the fly. The 
larvae can be found at all seasons of the year, and it is likely that there 
is a continual succession of flies during the warmer months. 
In its external features, which the author describes at length, tho 
larva of Dicranota resembles that of the nearly allied Pedicia rivosa ; 
as to its nervous system, none of the ganglia lie in the head ; the annular 
muscles of the body-wall are very numerous ; the fat-body extends almost 
throughout the body. The alimentary canal is a nearly straight tube 
of unequal diameter ; from his histological observations the author con- 
cludes that this larva is well adapted for the study of the secretory 
changes which take place in a digestive epithelium. 
The blood is colourless, with numerous minute elliptical corpuscles. 
Both spiracles and tracheal gills are carried on the last segment ; while 
Chironomus, the larva of which also lives in mud saturated with water, 
has a closed and rudimentary tracheal system, with abundance of lnemo- 
globin in its blood, Dicranota has an efficient tracheal system distended 
with air, and no haemoglobin. 
As in many other aquatic Diptera, the pupa is notably smaller than 
the larva. 
Anatomy and Development of Male Genital Armature of Ortho- 
ptera.f— M. A. Peytoureau throws doubt on the generally accepted 
homology between the genital armatures of the two sexes in Insects. He 
finds that the chief parts of the male armature of Periplaneta americana 
are produced, at a late period, at the expense of asymmetrical buds of 
the hypodermis ; the female armature is derived from parts which belong 
to the eighth and ninth urosternites. 
J3. Myriopoda. 
Cerebral Nuclei of Myriopoda. J — M. J. Chatin, from his study of 
various Chilopod Myriopoda, finds three kinds of nervous elements in 
the frontal lobe of the brain. There are normal nerve-cells which are 
generally unipolar or bipolar, have a large body and a globular nucleus 
whose chromatic power varies in intensity. Other nerve-cells have one 
or several nuclei ; these nuclei stain feebly. Thirdly, there are small 
cells with an average measurement of 4 p , which have a nucleus so large 
that the body is often reduced to a delicate peripheral zone of proto- 
plasm. It is clear that all these elements are cellular, and it is impos- 
sible to admit the existence of free cerebral nuclei. 
* Trans. Entomol. Soc. LoncL, 1893, pp. 235-53 (4 pis.), 
f Comptcs Rcndus, cxvii. (1893) pp. 293-5. % Tom. cit,, pp. 291-3. 
