. Journal of entomology and zoology. ere recognized, two thoracic and one abdom-inal. Sommer in 85 found four nerve centers below the head,three of these are called thoracic and one abdominal. Lubbock73 found three ganglia in the thorax and abdomen of Tomo-cerus. Linear species of Collembola are described as usuallyhaving two thoracic and one abdominal ganglion. Fernald 87in Anurida, recognizes pro-, meso- and metathoracic last of these seems composed of two ganglia. There are a number of other papers which describe or figurethe complete nervous system of some species of Collembola
. Journal of entomology and zoology. ere recognized, two thoracic and one abdom-inal. Sommer in 85 found four nerve centers below the head,three of these are called thoracic and one abdominal. Lubbock73 found three ganglia in the thorax and abdomen of Tomo-cerus. Linear species of Collembola are described as usuallyhaving two thoracic and one abdominal ganglion. Fernald 87in Anurida, recognizes pro-, meso- and metathoracic last of these seems composed of two ganglia. There are a number of other papers which describe or figurethe complete nervous system of some species of the more recent of these are those of Philiptschenko12, Hilton 13. As a rule two chief cephalic ganglia aredescribed and three others in linear species. JOTJKNAIi OF ENTOMOLOGY AND ZOOLOGY 39 In Xenylla the ganglia are mucli like those in Aphorurapreviously described. The supraesophageal ganglion is con-tinued towards the antennae on either side and these lobes arewell covered with nerve cells on the surface. The lateral por-. 0 0(3® CO Q. The figure at the top is a longitudinal section through the central nervous systemof Xenylla. 1 and 6 are the head ganglia; -2, 3 and i are the body ganglia; 5 is asection of the last ganglion at another level. The dorsal side is up. Inder 1,from A to S, are drawings of cross sections from another series through the headganglia at intervals in the nervous system of 5 microns. The dorsal side is u]).Under -2, there are similar sections shown from the first thoracic ganglion of thesame series. The sections run from A to H, every 5 microns. Lnder 3 and 4continuations of the same series are given through the two lower ganglia in thesame way. The dorsal side is up and all figures are drawn to the same scale, whichis X 200. 40 JOTJENAL OF ENTOMOLOGY AND ZOOLOGY tions of this ganglion are closely applied to the region of theeyes and the ocular lobes are evident as lateral extensions ofthe brain some distance from the connection with the sube
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