QUARTERLY CHRONICLE OF MICROSCOPICAL 
SCIENCE. 
GERMAN Y.—Zeitschrift f. wiss. Zoologie. Vol. xvii, Part 
2—I. **On the Oceluding Apparatus of the Trachee in Insects,” 
by Dr. H. Landois, and W. Thelen.—The first writer who 
pointed out the existence of a special apparatus for the closure 
of the tracheze was Burmeister,* who described and figured it as 
found in the larva of Ozyetes nasicornis. As the apparatus in 
question in this insect is placed very close to the stigma, Bur- 
meister concluded that it served for the closure of that part 
itself. But the authors of the present paper show that, in most 
instances, the occluding apparatus is quite independent of the 
stigma, and destined solely to the closure of the trachea. More 
lately three papers have appeared on this subject :—1. By L. 
Landois,t who describes the apparatus in question in the 
Pediculine ; 2. by H. Landois,t who studied it in the Lepi- 
doptera ; and 3. by W. Thelen,§ whose subject was Tenebrio 
molitor. 
The parts composing the closing apparatus are— 
1. The bow (Verschlussbiigel). 
2. The lever or axis (Verschlusshegel, or Kegel). 
3. The ligament. 
4, The muscle. 
The first three parts constitute a sort of frame-work sur- 
rounding the commencement of the trachea, and they are 
articulated together. The ‘ bow,” usually of a crescentic 
form, constitutes the firm basis of the apparatus ; and it sur- 
rounds about one half of the tube. The remaining portion is 
surrounded by a thin membranous ligament, which is drawn 
towards the “ bow” in a variety of ways, and thus effects 
the closure of the tube. In. some cases this approximation is 
effected by means of a simple chitinous rod connate with 
* ‘Handbuch der Entomology,’ theil i, p. 171. 
+ L. Landois, ‘ Zeitsch. f. wiss. Zool,’ xv, part 4. 
} ‘Archiv. f. Anatom., &c.,’ 1866, p. 43. 
§ Ibid., p. 391. 
