1884. | Entomology. 1047 
once their protective function. Similar glands, 7. e., with no 
outlet until one is produced by external agency, are not rare in 
bombycid larve. Karsten, in 1878, described the anatomy of the 
ison glands at the base of the hairs of an American Saturnia. 
he secretion is “ perhaps formic acid or a formate in solution.” 
e paper is crammed with interesting facts on this subject; 
among others it is stated that, according to Witlaczil, the “honey” 
secreted by the aphides issues from the anus, and not from the 
tubes on the sixth segment. : 
MALPIGHIAN VESSELS oF LeprpopTeRA—-M. Cholodkorsky has 
lately added Lineola bisel/iella to the list of the few insects that are 
nown to have only two Malpighian vessels; these are of some 
size, and are folded along the course of the digestive canal, and end 
by a distinct enlargement. Luckow has described four Malpigh- 
Jan vessels in a species of Pterophorus and of Hyponomeuta, but 
later investigations show that they really agree with the great 
Majority of the Lepidoptera in having six. As embryological Te- 
search has shown that a small number of Malpighian tubules is a 
primitive character, and that with progressive development the 
number'increases either by branching or by histolysis, succeeded 
by a fresh development of a larger number, it is clear that the 
Microlepidoptera in which there are but two, while their cater- 
pillars have six, exhibit just the reverse to what we should ex- 
pect, or in other words we have here a case of atavism, and one 
which as it obtains in the imaginal state only, is here a periodic 
rather than a constant atavism.—/ournal of the Royal Microscopi- 
cal Society, June, 1884, P. 373. 
TRANSMISSION, PRESERVATION AND MOUNTING OF APHIDES.—G. 
B. Buckton gives the řesults of his experience as to the best mode 
of transmitting living Aphides, and also the best method for kill- 
mg and preserving such like insects for future examination. 
is to transmission, the chief thing to be guarded against is 
desiccation, and no plan seems to be so ee gO hy ppa ETEA 
sure in ordin uills stopped by plugs of cork and pellets o 
beeswax, The substance of tthe quill is sufficiently porous to pre- 
vent mildew on the one hand and a rapid evaporation on the 
other. In this way small insects may be sent through the post, 
and in a far better condition than can be secured in any tin boxes, 
even though they be filled with leaves. If a slip of somewhat 
oo leaf be rolled round each quill, to retain moisture, a 
e will convenient! through the post. ° : 
For Preservation (aithen elit on a slide) the best plan is to drop 
the insects into small flattened glass tubes partially filled with a 
Suitable liquid, then draw the tube to a fine point, break the end 
off, and warm the empty space (or, better, expel the air by a 
Pump), and the tube can be entirely filled with liquid, and then 
Sealed with the blow-pipe. 
