. REVIEWS. 47 
mentary appendages, while in the flies (Muscidse and Corethra) 
they build up the whole body, according to the remarkable dis- 
covery of Weismann. 
The origin of the sting is clearly ascertained. Ganin shows 
that it consists of three pairs of tubercles, situated respectively 
on the 7th, 8th, and 9th segments of the abdomen* (Fig. 19, tg). 
The labium is not developed from a pair of tubercles, as is usual, 
but at once appears as an unpaired, or single, organ. The pupa 
state lasts for five or six days, and when the imago appears it eats 
its way out through a small 
Fig. 18. 
round opening in the end of the 
skin of its host, the Cecidomyia æ CoS 
larva. i AE ` 
Not less interesting is the his- 
tory of the development of a spe- F 
cies of Polynema, another egg- EB 
parasite, which lays its eggs & Şi z 
(one, seldom two) in the eggs of | Be 004 2% 
a small dragon fly, Agrion virgo, 1 20058 p 9,2 
which oviposits in the paren- R me ) oye oak 
chyma of the leaves of water- È D o“ 
lilies (Nymphea). The eggs de- RNG 
velop as in Platygaster. The <a LOO 
earliest stage of the embryo is 9%--------& 0 PNY 
very remarkable. It leaves the - ITTA, 
egg when very small and immoy- 
- able, and with scarcely a trace of Beeomi Tarva ot TETERE 
organization, being a mere flask-shaped sac of cells.} It remains 
in this state five or six days. 
*The riod in his “ Guide to the Study of Insects,” p. 14, and previously, in the 
Pr f the Boston Society of Natural History, vol. xi, p. 393, 1868, has shown 
that the ovipositor of Bombus s-arises from three pairs of garg like ge dp by 
zanin, but the two anteri oth ing from the’same(pennl- 
ate) he abdomen. It is mot improbable ie at an ges pero each 
pair arises from a hirer ate segment, as in Platygaster. Later inced 
e reviewer that these organs are ROMO | with Pe abdominal Jointed s stylets of of 
many insects, outh; and e 
wae _ % spring mor Poduræ. 
minds us (th in d tion it) of the pieng of the em- 
bryo of Julus, the Thou sand legs, dom pera: to Newport, hatches the 25th day 
er the egg is laid. At this period the embryo is partially organi: aar re om faint 
traces of Barini ts, and it is ae forelopen, in its embryona UE and retains 
its connection with the shell. en it 
throws off its em Aie l oana Tna ab cy Ae Ie th 
? 
