Chapter XII. 
INSECTS INJURIOUS TO THE HACKBERRY. 
By C. V. Riley. 
The Haekberry is one of the most characteristic trees in our American 
silva. What is said of the forms growing in Missouri in my sixth report 
on the insects of Missouri (1874, p. 137) will apply to other parts of the 
country in the same latitudes — in fact, throughout its range. 
Two tolerably constant forms are easily recognizable : 1. (occidentalis Linn.) with 
broad, ronghish, sharply serrate leaves, purple-black drupes, and rather pale bark, 
which on the trunk is rough and strongly cleft so as to look as if hacked. 2. (missis- 
sqypiensis Bosc.) with smaller, narrower, darker leaves, less serrate and often entire 
yellow drupes, and darker bark, the trunk appearing knotty. A third form (crassi- 
folia Lamk.), having more the aspect of Ulmus, occurs less frequently. It is much 
like occidentalis, but with more supple limbs and rougher, thicker leaves, which, 
when plucked, wilt more rapidly than do those of other forms. Botanists differ as 
to whether these forms are specific or varietal. Dr. Gray refers them all to Occident 
alis, and, as intermediate varieties are found and the seedlings from the same tree are 
exceedingly variable, this seems the proper course. But Professor Planchon, who 
has monographed the genus, considers 1 and 2 good species, and the third doubtful. 
In the report already alluded to (pp. 136 et seq.) under the head of 
" Haekberry butterflies," original accounts, with illustrations, will be 
found of the life-histories of two of our handsomest North American 
butterflies, which, so far, have been found to feed in the larval state 
exclusively on Haekberry. They are there treated of under the names, 
"Eyed Emperor" (Apatara lycaon), and "Tawny Emperor" (A. herse 
Fabr.), and the synonymy of the species is fully discussed and the 
reasons given for preferring the names of Boisduval and Le Conte 
{Apatura celtis and Apatura clyton). As the reasoning there has since 
been confirmed by the adoption of the latter names, both by Mr. W. 
H. Edwards and Mr. S. H. Scudder in their catalogues, these names will 
be used in the present instance.* 
* Led by Mr. Scudder's previous writings to adopt the Fabrician names, I never- 
theless took some pains to get at the real facts, and concluded, after considerable 
correspondence, that there was no cause to change the conclusions which I had pre- 
viously expressed, that we have but two species of Apatura in the United States, viz : 
A. hjcaon Fabr. = celtis Boisd. — alicia Edw.; and A. herse Fabr. = clyton Boisd. =pro- 
serpina Scudd. But I admitted that there would ever hang a certain doubt about 
herse, and that had I the paper to write over again I would use the Boisduval names, 
because I believe that science is better advanced by the use of names based upon 
descriptions of the living animals rather than by unearthing such as are drawn from 
pencil (and often faulty) imitations, an<l which admit of doubt and dispute. "In 
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