Thd First Abdominal Segment of Embryo Insects. 
119 
slowiy on her hind legs and straightway there emerged two streams of a 
vaporous fluid from the upper angle of the thorax near the neck. These 
streams were directed forward, but at a slight angle outwardly and up¬ 
ward, that is when the insect was resting on a horizontal surface. When 
the matter discharged first leaves the orifice from which it is expelled, it is 
a milky fluid, but as it is apparently as volatile as ether, it almost instantly 
assumes the form of vapor and is projected at least six inches. This fluid 
has a most peculiar pungent or peppery odor and although the moisture 
from it dries away very quickly from any object with which it comes in 
contact, the odor is retained for a long time. The fluid when thrown 
against the hand has no perceptible effect on the skin, but I have been told 
repeatedly by the negroes that the effect upon the eyes is very painful.” 
Odoriferous organs are well developed in the Hemiptera. Everybody is 
familiar with the secretions emitted from the metathoracic pear-shaped 
glands, the duct of which opens by means of the osteoles between the hind 
legs. 
The Neuropteran lace-wings ( Chrysopa) are characterized by a powerful 
and very unpleasant odor. 
Passing to the Coleoptera, many Carabidse, that produce from their anal 
glands secretions containing formic and butyric acid might be mentioned. 
Every collector of our native Coleoptera must have noticed the very 
powerful secretion produced by our common Chlaenius sericeus when 
captured. The bombardier-beetles [Brachynus], are well known for their 
habit of emitting clouds of pungent secretion accompanied by decrepita¬ 
tion. Loman [ ’87] has recently asserted that the gaseus secretion of the 
anal glands of the Paussid Cerapterus 4- maculatus contains free iodine. 
Among Cerambycids the European Aromia moschata has a powerful musky 
odor and the allied Callichroma plicatum, emits a strong honey-like smell 
according to the statement of my friend Mr. F. Rauterberg, who has col¬ 
lected numbers of these beautiful insects in Texas. The members of the 
genus Meloe exude oily drops of cantliaradin from the joints of their legs 
when disturbed. The Coccinelloe have a similar habit of exuding a deep 
yellow liquid. The Tenebrionidae are usually supplied with some un¬ 
pleasant secretion. 
Odoriferous glands occurs both in larval and imaginal Lepidoptera. 
Fritz Mueller has studied the scent glands [Duftflecken] on the wings of 
numerous South American Lepidoptera (’86 a — e). The forked protrusile 
gland of Papilio larvae and the pungent odor which it diffuses is well known. 
Its structure has been described by Klemensiewicz [ ’82]. One of our com¬ 
mon species of Pieris has redolent wings. According to Maynard [ ’89] 
- the exquisite little Bombvcid Utetheisa bella “ exudes an orange colored 
fluid from its thorax that has an unpleasant odor.” According to Packard 
the larva of Lochmoeus tessella, Pack, when disturbed sends out from each 
side of the body a shower, or spray of clear liquid. “ The opening of the 
gland is in the lower anterior part of the prothoracic segment”. Poulton 
