Article beginning on page 352.
Psyche 3:352-353, 1880.

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PS YCHE.
PUPA.
Length, 4 mm. ; breadth, 2 mm.
Enclosed within the larval skin, and
visible only from above, where the larval skin is longitudinally split open along the median dorsal line from head to anal seg- ment. Abruptly narrows to a point at the anal extremity. Removed from larval
skin, the entire surface of the pupa is seen to be covered with short, soft, light yellow- ish brown hairs, except at the centre of dorsal surface which contains three minute transverse incisions or furrows. The ante- rior margin of each furrow is straight while the posterior margin is curved. Examined under the microscope, Loth margins of each incision are seen to be minutely dentate, but the teeth of the posterior margins are more prominent than. those of the anterior margins. The incisions being in the outer layer of the skin only, these minute teeth may be of use in fixing the pupal skin
while the imago emerges from it.
The images, first appearing about the
middle of March, continue to appear during all the spring and summer months.
For several years this was the only
museum pest whose presence was dreaded
in the entomological cabinets of the Uni- versity of Kansas, but for the past three years Anthemis va'i,ius has become quite as formidable a foe, having been introduced into the building in some eastern bird skins. Careful watching and the use of tight boxes have prevented serious damage to the col- lections from either of these pests.
ORGANS, PROBABLY DEFENSIVE IN FUNCTION, IN THE LARVA OF HYPEKCHIRIA VARIA, WALK. (SATURNIA 10, HARRIS). BY GEORGE DIMMOCK, CAMBRIDGE, MASS.
In examining a larva of Hypercl~iria
varia lately I found on each side a protru- sile organ just posterior to, and a trifle below the level of the stigmata of the
fourth segment, and a similar organ in the same position relative to the stigmata
of the tenth segment, these segments
being counted from and excluding the
head.
These organs, when retracted, exhibit
nothing more than an irregular opening,
about half a millimctre in diameter, sitna- ted in the reddish lateral line which extends from the anterior part of the fourth seg- ment to the posterior extremity of the
larva. In this position they may be easily mistaken for some of the folds of the skin which are numerous along the lateral parts of this larva when at rest.
If the larva be disturbed by slightly
touching the spines with which it is covered, and at the same time attention be given to the above-mentioned irregular opening's, which should be observed under a lens,
each opening will be seen to evaginate and to re-invaginate alternately. When evag- inated to about a half a millimetre in
height above the surrounding skin the
appearance of the organ is very similar to that of a minute sea-anemone or actinia




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PSYCHE.
with its tentaeleyretracted, and this resem- bltince is enhanced Iff the flesh-like aspect of the whole extended portion of the organ, its color being about the same a3 that of the reddish lateral line in which it is situ- ated. The organ is usually evaginated,
as above described, upon any slight distur- bance of the larva, to a distance of about ' -75 mm,
If the larva is greatly disturbed, espec- ially s'uddeuly, as by a sharp, quick stroke on the spines or hy a pinching of the skin, the organ is sometimes further wag-hated, a moment only, to over a millinletre in
length. The distal extremity, when fully cvaginatcd, is 'rounded, being; tciininated by a hemispheroidal portion of more deli- cate textnre and of sliglitly lighter color than the proYitiial portion.
This organ is probably the opening of a
gland, altho it never appears moist. The abundant moisture, however, which usually indicates glandular secretion in insects is not a necessary character of such secretion, any more in insects than in wrtebratcs.
Silk and the woolly masses on aphides are examples of nearly dry solid secretions in insects, while the gas, permanent under
ordinary conditions, which is emitted from the anal glnnds of Brachiwis shows that
an. insect, seui-etion may either be gaseous or become gas directly upon its emission, So the absence of appreciable moisture is no sure proof that the organs under consid- eration are not glandular. There is no
odor about these organs; as far as I could determine, nor did their surface show either acid or alkaline reaction upon being touched with moistened litmus paper.
The ftmction of these organs seems to
be to defend tlia larva, already so thoroughly protected from many dangers by its urtioa- ting spines, from some kind of atlack, for the orgaus arc not in use when the larva is undisturbed and are more active in their protrusion and retraction the more die
larva is disturbed. Their function may
be to drive away some parasite, fbi' against the attacks of ichneumons the sharp spines of this larva are au inadequate defense. The improbability of four such organs
as those described above escaping the notice of all the entomologists who had carefully examined the larva of Hyperchiria varia
led me to look up ail the accessible doscrip- tiona of that larva, hut I found no mention of these organs in way of them. Harris,
in his Entomological Correspond~nce,~ and Riley, in his Fifth K~port,~ give quite
extended descriptions of the larva and locate the different series of spicuiiferoiis tuber- cles, but entirely overlook the organs which are the subject of this note,
As I have ueithcr time nor material for
the extended study of these organs I pub- lish this brief note on their external appear- ance in the hope that some one will study them further, especially in regard to their internal structure and to determine their functions with certainty. It would be of interest to note whether the larva possesses these organs in all its different stages, a point which I was unable to settle because of having no very young larvae.
Cambridge, 7 Sept. 18S2.
1 Oecasinnd papers of the Boston swiety of natural 11 isiury. I, Enton~ological correspon- denceof TLmideus Wiliinm Hnnis, M. 1). Edi- tedby Snmuel H. Scurlder. Boston, 18G9. p. 29.5-207.
2 Fifth annual Report on the noxious, benefl- rial and other insects of the state of Missouri, , . . by C. V. Riley, state entomologist. Joffer- son City, 1873. p. 135.




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