ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
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inferior aspect of the thorax. It is structurally comparable to the man- 
dibular gland, and has been described by Meinert and by Lubbock in 
Formicinee, where however its structure is rather different from that in 
Myrmicinee. The cavity into which the gland opens is an almost closed 
air-chamber. It is probable that the secretion is volatile, and Janet 
hazards the suggestion that it is the source of the characteristic “recog- 
nition-odour.” 
Heart of Hive-Bee.* — Herr W. J. Pissarew finds in Apis mellifica 
that the “ aorta,” after bending down to the left side of the gut, shows 
eighteen well-defined zigzag loops, which become shorter anteriorly, and 
stop about the beginning of the thorax. There is a hint of these loops in 
Cheshire’s figures. The author inquires as to their possible use, whether 
they occur in any other insects, and whether the vessel on which they 
occur should be called “ aorta.” 
Brain of a Cave-Beetle.t — Herr 0. Hamann has investigated the 
central nervous system of Leptoderus hohenwarti Schmidt, a blind beetle 
belonging to the family Silphidm, and occurring in the recesses of the 
Adelsberg cave. The supra-oesophageal ganglia show pear-shaped 
swellings, which are continued into the antennary nerves, but there are 
no other nerves given off. There is no hint of eyes or optic nerves. A 
very broad connective round the gullet connects the supra-oesophageal 
with the sub-oesophageal mass, the latter being very well developed. 
Herr Hamann notes the superiority of 10 per cent, formol over alcohol 
for the preservation of such specimens as the above, if histological 
examination is in view. 
Venation of a Typical Insect Wing4 — Messrs. J. H. Comstock and 
J. G. Needham point out that the recognition of the features of the wing 
venation that are common to the various orders of insects has been a 
matter of slow growth. The names and abbreviations to which the 
authors adhere are Costa, C; Subcosta, Sc; Radius, B; Media, 31; 
Cubitus, Cu ; Anal veins, A. 
Growth of Butterflies’ Wings.§ — M. Arnold Pictet describes the 
growth of the wings in Rhopalocera after emergence from the chrysalis. 
Composition of Insect’s Head. ||— Herr R. Heymons concludes that 
in insects the frons, clypeus, labrum, compound eyes, and frequently the 
whole anterior portion of the occiput, represent parts of the primary 
head segment, while the posterior portion of the occiput and the genre 
represent, probably exclusively, the tergites of the jaw-segments. 
Chromatin Reduction in Hemiptera.lf — F. C. Paulmier points out 
that the subject of chromatin reduction in insects is at present in con- 
siderable confusion. The four workers who have done most to it — 
Henking, vom Rath, Wilcox, and Montgomery — have reached quite dis- 
similar results. He has studied it in a number of species of Hemiptera. 
Anasa tristis de G., Euchistus variolarius Pal. Beauv., and others, and the 
* Zool. Anzeig., xxi. (1898) pp. 282-3 (1 fig.). 
t SB. Ges. Nat. Freunde Berlin, 1897, pp. 1-3. 
X Amer. Nat., xxxii. (1898) pp. 81-9 (1 fig.). 
§ CR. Soc. Phys. Nat. Geneve, 1898; Arch. Phys. Nat., v. (1S98) pp. 378-81. 
|| SB. Ges. Nat. Freunde Berlin, 1897, pp. 119-23. 
f Anat. Anzeig., xiv. (1898) pp. 514-20 (19 figs ). 
