MEMOIES OP THE NATIONAL ACADEMY OF SCIENCES. 
9 
the tyi^e species is the most modified, that most uulike its congeners, 'uuless, as is often the case, it 
happens to have been the first one of its genus to have been discovei'ed and described. 
We have thought it better and more i)hilosophical to begin with that species whose larva is 
the most simple and generalized, and then arrange in their natural order those whose larva? are 
more and more si>ecialized or modified, as regards the number and variety of their markings, or 
the comiilexity of their armature. In the genus Ichthyura, for exam]»le, the larva of I. apicalis 
(van) is the most simple and generalized, not having the high tul)ercles and bright varied mark- 
ings of 7. hiclusa and albosigma. 1 have therefore supposed this to have been the first species to 
have evolved, and this decision is supported by the wide distribution of the species and the rather 
large number of varieties and subvarieties into which the form has been broken up. 
In the case of the imago, that species which has plain wings without complicated bars and 
spots is more primitive than those with more coini)lex niurkings. 
This course may at times lend to error and uncertainty, and involve more or less hypothesis 
or guesswork, but the simple attempt will lead to a more careful scrutiny of the larval character- 
istics, and to a profounder, more thorough, and better knowledge of the biology of the genus, and 
that of course is the aim in such work. Of course the systematic part of this or any other work 
of the sort is a necessary i)relimiuar 3 ^ to all other higher endeavors to a complete history of the 
group from a morphological and biological point of view. 
On this account it is, we think, a great pity that some of the compilers of our check lists of 
Lepidoptera and other insects, and of our zoological text-books and other works of the sort, still 
persist to cater to the tastes, rather than true needs, of amateurs and collectors by beginning at 
the wrong end, i. e., with the “highest’- forms rather than with the “lower” or more primitive. 
Such lists and works would have a far higher educational value and lead to much better mental 
training if such compilers could have had some knowledge of the immense impetus given to the 
science and the new waj' of dealing witli s^xstematic zoology which has resulted from the labors 
of Darwin, Fritz IMiiller, Weismann, and others. 
Ill describing cateriiillars, particularly those of the Bonibyces, I have been particular to dis- 
tinguish between tlie three thoracic and the ten abdominal segments, because the former usually 
differ from tlie abdominal segments in the number, arrangement, and relative size of the tuhcrcles, 
warts, and other markings. The warts or tubercles also are grouped into dorsal, subdorsal, 
and supraspiracnlar rows (though this latter may in some cases be the subdorsal row), aud an 
infraspiracular row or series. 
In order to obtain further material to finish and to perfect this monograph of the Bombyces, 
the author would like to obtain from collectors and students in all parts of the country’-, especially 
in the Southern, 'Western, and Pacific States, the egg, larvie, or moths, in order to fill up gai>s, as 
well as to afford material for illustration. 
Should anyone rear any of these Bombyces, with a view to publication, I should be greatly 
obliged for alcoholic specimens of the eggs aud difierent larval stages, which might be sent after 
such descriptions were published.^ Such specimens would be carefully" kept and returned. It will 
only be by such cooperation that wo shall arrive at a fair knowledge of the transformations of 
this extensive group. 
This monograph could uot have been i>repared without generous aid from friends aud cor- 
respondents, as well as from those in charge of the several museums mentioned below, whose 
hearty cooperation I now acknowledge. 
I am specially indebted to Prof. G. Y. Eiley for the opportunity of freely examining from time 
to time his extensive collections, so rich in preserved larvin, both blown and alcoholic, the result 
of years of labor while residing in Illinois, St. Louis, and in Washington, D. G. After presenting 
them to the United States Natiou<al Museum, he has continued to allow me to examine the Bom- 
bj^ces, and loaned me specimens of larvie as w'ell as moths for study and illustration. He has also 
permitted the use of numerous colored sketches, made by himself or his assistants under his 
^ It is earnestly hoped that anyone receivin’^ this memoir will kindly reciprocate by sending the eggs aud larv£e 
of any Bombyciiie moths not herein described, packed in tin boxes, to tbo author, at Providence, R. I., or during 
July and August, at Brunswick, Me. We still lack the eggs and young larva? of Ellida, Lophodonta, Drymonia, 
and Xotodoiita. 
