420 SUMMARY OF CURRENT RESEARCHES RELATING TO 
four that have been described by European naturalists, and enters into 
some details with regard to the anatomy of the Japanese form. 
Arthropoda. 
a. Insecta. 
A Manual for the Study of Insects.* — Prof. Comstock has prepared 
an elementary systematic text-book, designed for the use of students in 
high schools and colleges, and for teachers in primary and secondary 
schools. Its most distinctive feature is a series of analytical keys, by 
means of which the family to which a North American insect belongs 
can be determined. The author believes it is so arranged as to make it 
possible for the student to classify any insect to its family, and to learn 
the habits of the insects of that family ; while, in the case of the more 
common species, he may also learn the name of his insect. The number 
of figures is large, and as they have been specially prepared for the 
work, we are saved the disagreeable rencontre with old friends which we 
frequently have in so many manuals. Prof. Comstock has devoted him- 
self for many years so closely to the classification of Insects, that the 
work is probably one which has more than an ordinary value. 
Integument of Insects. +- -Dr. J. Vosseler has discovered in the 
integument of insects two layers of different physical and chemical 
characters. Externally there is the chitinous layer, and internally there 
is a layer which completely agrees with cellulose. The cellulose may 
be obtained by chemical reagents from the skin of insects. 
Epidermic Cells of Insects. :£ — M. J. Chatin finds that cuticular and 
other modifications are due to the reticular hyaloplasm of the epidermic 
cells. The viscous protoplasm meantime becomes more granular and 
more abundantly pigmented. Similarly, during the process of cuticu- 
larisation, the nucleus exhibits changes, showing the intimate solidarity 
of cytoplasm and nucleoplasm. It elongates, curves upon itself, becomes 
horse-shoe shaped, and so on. 
Miocene Insect Fauna of (Eningen, Baden.§ — Mr. S. H. Scudder 
has lately had the opportunity of examining a large collection of fossil 
insects from this place, consisting of about 3500 specimens, of which 
fully one-half may be made use of to advantage. From the better speci- 
mens the author has separated over 400 species. From a table which he 
gives, it appears that the relative number of species in the different 
orders is almost strictly identical in his enumeration and that of Heer. 
It enables one to assert with much assurance that in number of species 
the Coleoptera of (Eningen are vastly preponderant, including about 
two-thirds of all. They are followed by the Hemiptera, and they by 
the Hymenoptera ; the Diptera are a good deal less numerous, while the 
Neuroptera and Orthoptera are feebly represented. For the first time a 
true Acridid has been recognised. Among the Diptera there is a new 
generic type allied to Tabanus , and there is a single specimen of a 
* ‘ A Manual for the Study of Insects,’ by J. H. Comstock and A. B. Comstock, 
Ithaca, N.Y., 1895, 8vo, vii. and 701 pp., 797 figs. 
f Jahresh. Ver. Naturk. Wiirttemberg, 1. SB. pp. Ixxxv.-lxxxvi. See Zool. (^n- 
tralbl., ii. (1895) p. 117. I Comptes Rendus, cxx. (1895) pp. 1285-8. 
§ Geol. Mag., ii. (1895) pp. 116-22 (1 pi.). 
