INSECT POWDER. 25 
also because it is considered more expedient at this time to place 
the greatest emphasis upon those diagnostic characters whereby 
commercial powder may be accurately analyzed microscopically. 
Siedler's (150) (258) morphological description of the Dalmatian 
flowers, which is quite in detail, may be summarized as follows: 
The Dalmatian flower stem is 8-sided and very hairy; receptacle 
slightly arched; involucre consisting of 3 rows of scales, the inner 
scales lanceolate and about 4 mm. long, the scales of the middle row 
about 6 mm. long. All of the scales have a flat inner surface, the 
outer surface being more or less keeled, possessing a scarious margin 
and covered with hairs. The whitish ray flowers measure about 15 
mm. in length and 4 mm. in width, 3-toothed at the tip, the middle 
tooth being somewhat smaller than the other two. The disc flowers 
are tube-shaped and 5-toothed, possessing the typical Composite oil 
glands and containing more or less of the yellow, 3-pored, spiny pollen 
grains. The fruits of the ray flowers exhibit a different structure 
from those of the disc flowers, being somewhat flattened on the side 
lying next to the outer bracts, and possessing 2 furrows, while the 
inner side has 3. The fruits of the disc florets consist of 4, sometimes 
6, nerves. A small crown is present on all the fruits. 
Collin (47) designated 3 distinct commercial varieties of Dalma- 
tian insect flowers : 
1. Closed flowers. — Flower heads, varying from 3 to 7 mm. in 
diameter, generally furnished with a very short striated peduncle. 
Bracts, greenish-yellow, closely appressed. Corollas of ligulate 
florets almost always entire; grayish- white in color, and wrinkled 
and shriveled over the tubular florets, so as to conceal them almost 
completely. Very few expanded flowers present; very few frag- 
ments of corollas, ovaries, or bracts mixed with flower heads. 
2. Half -closed flowers. — Peduncle longer, even 4 or 5 cm. long. 
Flower heads full, bracts with a yellowish-gray color. Ligulate 
florets can usually be distinguished; tubular florets still retain their 
corollas more or less intact. 
3. Open flowers. — Recognized by the size of the flower heads, 
many of which attain a diameter of from 9 to 11 mm. Usually 
completely expanded when gathered and hence few of them intact; 
some ligulate florets destitute of corollas and in many others the 
corollas of the tubular florets have been separated from the ovaries' 
which remain attached to the receptacle. This variety contains 
abundant debris of the corollas and ovaries, and therefore is not as 
choice commercially as classes 1 and 2. He described the various 
parts of the Dalmatian flower head as follows: Bracts, outermost 
thicker and shorter than the others; more strongly curved and more 
pointed at the apex; those from the middle row lanceolate, slightly 
curved; the inner scales are as long as the middle ones but thinner 
