1884.] Entomology. 535 
length, their extremities recurved within the containing sac, and 
their tips not at all swollen, but rounded off. “ As they are elas- 
tic, and the closing sac distensible, we think it highly probable 
that with each water-inspiration the sacs enlarge and the tracheal 
spray (having air forced in by the forward compression of the 
rge tracheze) spreads out so as to bring the full tide of air close 
to the tide of water. Léon Dufour, seems to have had some pro- 
Felished in Feb., 1884!), states, that if a Cecropia caterpillar 
yellow knobs, or tubercles, will be seen to break easily from the 
peecis, and a clear, yellow fluid of disagreeable odor to ooze 
sy each opening left by the injury. By crushing the tubercle 
a 
and by 
that each tu 
fl 
wa n E odorous fluid pours, pushed by internal pressure. 
a ras which I have not examined carefully, but which I hope 
a study chemically, is strongly acid to litmus paper, but 
out et precipitate in carmine solution.” The odor given 
e 
| ey i cts on this subject. Among others it is stated that, 
: issues free to Witlaczil, the “ honey ” secreted by the Aphides 
k om the anus and not from the tubes on the sixth segment. 
Sated eon. Mu TURE oF Insects. — C. Luks has investi- 
racic musculature of insects of every group, except 
