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Psyche 6:11-12, 1891.

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January 1891.1 p6'2THl?. 11
Hylotoma scapularis Klug. -The full-
grown larvae have a pretty general resem- blance to those of H. $ectoralis Leach {-=H. dulciarirz Say),* and are about 18 mm. long. Head light orange yellow, body somewhat
flattish and light yellow-ish green in color. There are six distinct rows of small closely adjoining black spots on the upper portion of the body extending from the head to the anal segment. On each of the fleshy projec- tions on the sides of the segments, except the last, there is an oblong dark spot; but these spots above the two posterior pair of true legs appear as two large somewhat tri- angular black blotches. Above the anal seg- ment there is a large oval shaped black spot. The legs are black on the outer side, and the prolegs are marked by a dark brown blotch on the outer side. The black legs and black blotch on the anal segment are the chief marks which distinguish this larva from that of H. pectoralis in which the legs and anal segment are yellowish. The cocoons are of a dirty while or light brown color and aver- age about 12 mm. in length. They are com- posed of two walls, the inner being closely, and the outer loosely spun.
The eggs are deposited along the margins of the leaves of the common American elm (Ulmzrs Americana) upon which the larvae feed. Young larvae were found early in Au- gust and those observed attained full growth about the end of the month. Two males
and many females were raised from these
about the first of July following.
Hylotoma McLeayi Leach, Full grown
larva from 15 to 18 mm. long. Head black. Body flattish; pale yellowish green, with four distinct lines of black spots along the back extendingfrom the head to the anal seg- ment; and with some minute, less regularly arranged spots or dots along the sides above the fleshy projections which characterize lar- vae of this genus. Each fleshy projection bears a long narrow black spot. The anal segment is surmounted by a large irregular oval black blotch and is brown above the anus The legs are dark brown or black on the outer base and have a heavy black blotch at the base. The prolegs are marked on their outer side by a somewhat triangular, black or very dark brown spot. The cocoon is
double walled; the outer wall being loosely woven and it is dull white or pale brown in color, and is from 12- 14 mm. in length. The larvae were found in considerable
numbers in the month of August feeding
upon the foliage of common choke-cherry
(Pruniis Virgtkiana) at Jamaica Plain, Mass. From these larvae a number of female im- ages were bred in the latter part of the month of May following.
A NOVEL DIAGRAMMATIC REPRESENTATION OF THE ORDERS OF INSECTS.?
The difficulty of representing satis-
I] shows by parallel bars rising above
factorily by any linear arrangement the
the circular plate, which represents the relations of the orders to each other surface of the earth, the sixteen orders of and to Thysanura has compelled us to
insects as they exist to-day, and below
give diagrams 1-111. Diagram I1 [pi.
this plate the different ordel-s are ar- -
*See T. W. Fyles in Canadian entomologist, v. 18, t Reprinted from Guides for Science Teaching. No. P. 38; V. 19, P. 59.
VIII. Insecta. By Alplieus Hyatt and J. M. Arms. Ps\&e 6 01 1-H (pre.1903). hfp //psyche aitclub orgt#6-0011.himl



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12 l's2‰Û÷-cH [January 1891.
ranged in converging bars according to
their supposed relations during geologic times. This last is purely theoretical,
since the present state of our knowledge of fossil insects is too fragmentary and unsatisfactory to afford sufficient evi- dences for the demonstration of such a
classification.
Diagram I1 [pi. I] represents the op-
posite or farther side of Diagram I,
the plate having been turned around
so that the orders X-XVI can be more
clearly seen both above and below the
earth's surface. Diagram I11 is a view
from above the circular plate giving in
horizontal section the position of the
orders. In Diagrams I, 11, A repre-
sents the wingless, primitive, or Thy-
sanuran stock. The stems å£ B",
B"' * , Diagram I ; B', ^Iv, Diagram
11, represent the winged stocks which
sprang from A. These may have been
composed, so far as the facts now known
are concerned, of a number of separate
or branching lines leading up to the
various orders as termini of more or
less distinct stocks.?
The line B' in Diagram I1 indicates
the winged stock from which the true
Neuroptera sprang, and so far as we
know,
Diagram 111.
this may have been the siirne
common stock as that from
which the Epheimeroptera and
Odonata also arose (Diagram I,
22). In spite of the introduction
of the quiescent pupal stage in
the Neuroptera, their obvious
resemblances to the Odonata,
and the fact that they still retain
the Thysanuroid form of larva
should not be overlooked.' Dia- ,
gram I recognizes these simi-
larities, and presents the least
modified and most ancient
branches of the genealogical
tree of the Insecta as near to-
gether as practicable. The
placing of Thysanura near the
centre, by means of a short
* 231 1
extends in the diagram to the orders He~niptera and Tliysanoptera instead of to the stem from which these orders sprang. It is placed here because the stem proper is out of sight, being farther down and behind B and 23I I.
f For example;, as suggested by Packard in Third Rep. U. S. Ent. Corn., p. 289, the Dermaptera may have been derived from a form similar to Japyx, a curious Thysanuran genus, and since it has characters allying it both to Orthoptera and Coleoptera, it may be the existing descendant of some common forms from which both of these orders originated. The Thysanura stand, according to Coqstock, in a similar position with relation to the Hem- iptera.
Ì




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January 1891 .]
vertical line ,* indicates the essential- ly generalized and larval character
of the order, and does not necessarily
imply any nearer relationship to Neu-
roptera, which stands on the right,
than to Coleoptera on the extreme left.
The height to which the vertical bars
have been carried above the plate is a
rough approximation to the specializa-
tion attained by the adults, and also to the removal of the mode of development
from the primitive Thysanuroid mode.
The orders existing to-day are re-
garded as parallel series differing from each other in structure, and not as yet
connected by well-known intermediate
forms. Where the probability exists
that certain orders have had a common
origin, they are placed on the same
radiating lines, as seen in Diagram 111, orders 11-111 ; also VI-VII, and VIII-
IX; and this rule has been departed
from only where the data seemed to
justify a more natural interpretation, as in the case of the orders from XI1 to
XVI, inclusive.
All of these graphic presentations
are necessarily extremely rough approx
imations to the actual facts, and present even the authors' views in a very im-
perfect manner. Nevertheless, if con-
scientiously studied, they will, it is
hoped, help to give teachers some ideas
of the principles upon which a classifi- cation is based, and prevent them from
falling into the absurd but natural mis- takes often
occasioned by the linear
treatment of types in the text.
LIST OF ORDERS.
I. Thysanura.
11. Ephemeroptera.
111. Odonata.
IV. Plecoptera.
V. Platyptei-a.
VI. Dermaptera.
VII. Orthoptera.
VIII. Thysanoptera.
IX. Hemiptera.
X. Coleoptera.
XI. Neuroptera.
XII. Mecoptera.
XIII. Trichoptera.
XIV. Lepidoptera.
XV. Hymenoptera.
XVI. Diptera.
DESCRIPTIONS OF THE LARVA AND PUPA OF SCOTOBATES CALCARATUS FABR.
BY WM. BEUTENMULLER, NEW YORK.
LARVA :-Head subquadrate, anterior angles obtusely rounded, sides moderately rounded. shining. Clypeus tranverse, about three
times as broad as long, oblique. Labrum
smaller than the clypeus, anterior margin rounded and beset with a few bristle-like hairs. Antennae three jointed, first joint cylindrical, about twice as long as broad; *See also the diagram given by Packard in Third Rep. U. S. Ent. Corn., 1883, p. 295.
second joint considerably longer, clavate; third joint minute, cylindrical, with a few hairs at the apex. Mandibles short, stout, arcuate externally, excavate internally, apex tridentate, base with a prominent elevation with two small teeth. Maxillae subcylindri- cal, stout, elongate, lobe somewhat
truncate
at the apex with a number of bristle-like hairs. Maxillary palpi three jointed, first joint stout, cylindrical, broader than long;



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