68 The American Naturalist. [January, 
may be, it would appear, that they are in that early stage quite indis- 
tinguishable from other blastoderm cells. 
“ Therefore, it would appear, that whilst the great mass of cells become 
differentiated into various structures which subserve a special purpose, 
or perform their several functions, certain cells in the ovary retain 
their primitive condition, and with it the power, under suitable condi- 
tions, of forming another individual of the same species. On this 
subject Mr. Woodworth writes: ‘About the time of the completion of 
the blastoderm, the already differentiated ventral plate infolds at a 
point on the median line about two-thirds from the upper end, and 
forms a very narrow pocket. The cells composing it look like the 
rest of the cells of the ventral plate at this time, they are almost 
round, and have a lining on one side made of the grey matter which 
originally bordered the whole egg, but which became a part of the 
blastoderm cells. The pocket remains open but a short time, but there 
is a long depresssion of the upper end of the bunch of cells ; the mass 
of cells is soon cut off from the ventral plate and they are then free in 
the body cavity, but remain in contact with the ventral plate at the 
point where they were produced. Later stages show that these cells. 
produce the generative organs; the generative organs thus appear to 
be produced by an infolding of the ectoderm, or possibly of the blasto- 
derm, before the ectoderm is produced, but from a portion which is 
later to become ectoderm.’ 
Alimentary Canal in Orthoptera.—Dr. F. Werner has com- 
pared‘ the relative length of the intestine in vegetarian and insectivo- 
rous Orthoptera. The result was unexpected. The plant-eating 
Acridiidæ have a short, almost straight gut, rarely larger than the 
body ; while the Locustide have a longer gut usually spirally coiled,. 
especially in Barbitistes and Phaneroptera. Werner believes that the 
length and coiling of the intestine have nothing to do with the diet, ` 
but are correlated with the shape of the body and the habits of life.— 
Journal Royal Microscopical Society. 
North American Jassoidea.—Mr. Edward P. Van Duzee has 
panned an excellent Catalogue of the Described Jassoidea of North 
America.’ It covers more than fifty pages, and is especially full in 
bibliography and synonymy. “The classification and arrangement 
here adopted is substantially that proposed by the author in his ‘Synop- 
* Biolog. Centralbl., XIV, (1894), pp. 116-9. 
5 Trans. Am. Ent. Soc., XXI, July, 1894. 
