considering that the various types of insects are descended 
from ancestors more or less resembling the genus Cam- 
podea, with a body divided into head, thorax, and abdo- 
men-; the head provided with mouth-parts, eyes, and one 
pair of antennz, the thorax with three pairs of legs, and 
the abdomen, in all probability, with caudal appendages. 
If these views are correct, the genus Campodea must 
be regarded as a form of remarkable interest, since it is 
the living representative of a primzeval type from which 
not only the Collembola and Thysanura, but the other 
great orders of insects have derived their origin. 
This ancient type may possibly have been derived from 
a less highly developed one, resembling the modern Tar- 
digrades, a (Fig. 56) smaller and much less highly 
organised being than Campodea, which has been succes- 
sively placed among the Acari and the Rotatora. It 
possesses two eyes, three anterior pairs of legs, and one 
at the posterior end of the body, giving it a curious re- 
semblance to some Lepidopterous larvez. 
These legs, however, as it will be seen, are reduced to 
mere projections. But for them, the Tardigrada would 
closely resemble the vermiform larva so common 
among insects. Among the Coleoptera, for instance, the 
vermiform type occurs in the weevils ; among Hymenop- 
tera in the Bees and Ants; among Diptera it is general. 
Among Tricoptera the larva early acquires the three pairs 
of legs, but as Zaddach has shown,* there is a stage, 
though it is quickly passed through, in which the divisions 
of the body are indicated, but no trace of legs is yet pre- 
sent. Indeed, there appear to be reasons for considering 
that while among Crustacea the appendages appear be- 
fore the segments, in Insects the segments precede the 
appendages, although this stage of development is very 
transitory, and apparently, in some cases, altogether sup- 
pressed. I say “apparently,” because I am not yet 
satisfied that it will not eventually be found to occur in 
all cases. Zaddach, in his careful observations of the 
embryology of Phryganea, only once found a specimen in 
this stage, which also, according to the. researches of 
Huxley, + seems to be little more than indicated in 
Aphis. It is therefore possible that in other cases, when 
no such stage has been observed, it is not really absent, 
but, from its transitoriness, has hitherto escaped at- 
tention. 
Fritz Muller has expressed the opinion f that this ver- 
miform type is of comparatively recent origin; he says, 
“the ancient insects approached more nearly to the 
existing Orthoptera, and perhaps to the wingless Blat-. 
tidz, than to any other order, and the complete meta- 
morphosis of the Beetles, Lepidotera, &c. is of later 
origin.” “There were,” he adds, “perfect insects before 
larvee and pupz.” This opinion has been adopted by 
Mr. Packard § in his “ Embryological Studies on Hexa- 
podous Insects.” 
M. Brauer || also considers that the vermiform larva is 
a more recent type than the Hexapod form, and is to be 
regarded not as a developmental form, but as an adapta- 
tional modification of the earlier active hexapod type. In 
proof of this he quotes the case of Sitaris. 
Considering, however, the peculiar habits of this 
genus, to which I have already referred, and that 
the vermiform type is altogether lower in organi- 
sation and less differentiated than the Campodea 
form, I cannot but regard this case as exceptional ; 
as one in which the development has been, so to 
say, “falsified” by the struggle for existence, to use an 
expression of Fritz Miiller’s, and which therefore does not 
truly indicate the successive stages of evolution. On 
the contrary, the facts seem to me to point to the con- 
clusion that, though the grublike larvz of Coleoptera, and 
* Unters. ub. die Entwick, und der Bau der Gliederthiere, p. 73 
+ Linnean Transactions, v. xxii. 
1 Facts for Darwin, trans. by Dallas, p. 118. 
§ Mem, Peabody Academy of Science, v. I. No. 3. 
|| Wien. Zool. Bott. Gesells, 1869, p. 310. 
NATURE 
169 
some other insects, owe their present form mainly to the 
influence of external circumstances, and partially also to 
atavism, still the Campodea type is itself derived from 
earlier vermiform ancestors. Nicolas Wagner has shown 
in the case of a small gnat, allied to Cecidomyia, that 
even now, in some instances, the vermiform larvz retain 
the power of reproduction. Such a larva (as, for 
instance, Fig. 57) very closely resembles some of the 
Rotatoria, such, for instance, as Albertia or Notom- 
mata ; these differ generally in possessing vibratile cilia, 
There is, however, one genus—Lindia (Fig. 58)—in which 
these cilize are altogether absent, and which, though re- 
sembling Macrobiotus in many respects, differs from that 
genus in being entirely destitute of legs. I have never met 
with it myself, but it is described by Dujardin, who found 
it in a ditch near Paris, as oblong, vermiform, divided 
into rings, and terminating posteriorly in two short conical 
appendages. The jaws are not unlike those of the larvx 
of Flies, and indeed many naturalists meeting with such a 
creature would, I am sure, regard it as a small Dipterous 
larva ; yet Dujardin figures a specimen containing an egg, 
and seems to have no doubt that it is a mature form. * 
JOHN LUBBOCK 
(To be continued.) 
AMERICAN SCIENTIFIC EXPEDITIONS + 
‘Le present year will be pre-eminently characterised 
in the history of the United States by the number 
of scientific expeditions, thoroughly equipped in every 
respect, and fitted out for exploration in various regions 
of the great West ; and although most of them have been 
already referred to in our columns, it may be well to 
recapitulate them in geographical order. The most 
northerly is the International Northern Boundary Com- 
mission, which is intended to survey the line of the forty- 
ninth parallel, from the Lake of the Woods to the crest of 
the Rocky Mountains. The survey of the eastern section 
of the northern boundary of the United States was com- 
pleted many years ago by Colonel J. D. Graham and 
others, and that of the western section, from the Pacific 
coast to the Rocky Mountains, was brought to a close in 
1860. The middle section, as was the western, is in 
charge of Archibald Campbell, Esq., of Washington, as 
commissioner, with Major Twining as chief engineer 
officer on the part of the United States. Dr. Elliott 
Coues, of the army, the well-known naturalist, accom- 
panies the expedition in that capacity, and the work will 
be done in connection with a large party, equally well 
equipped, detailed by the British Government. 
The labour of this Commission was begun in 1872, con- 
sisting in the examination of the line from the Lake of 
Woods to Pembina, this village being the starting-point 
for the present year. 
The next expedition is that along the line of the 
Northern Pacific Railway, and will consist of a body of 
about 2,000 troops, under the immediate command of 
Colonel D. N. Stanley. This will concentrate at Fort 
Abraham Lincoln, on the Missouri, now representing the 
western terminus of the Northern Pacific Railway, and 
its route will be westward toward and across the Yellow 
Stone River. This large force is intended to keep the 
Indians in check, and prevent any interferences on their 
part with the location and construction parties of the 
railway. In view of the fact that this expedition passes 
through a rich but little-known country, abounding in 
objects of natural history and zoology, the president of 
the National Academy of Sciences memorialised the 
Secretary of War in reference to the appointment of a 
* See also the descriptions given by Dujardin (Ann. des Sci. Nat. 1851, 
v. xv.) and Claparéde (Anat. and Entwickl. der Wirbellosen Thiere) 
of the interesting genus Echinoderes, which these two eminent natu alists 
unite in regarding as intermediate be:ween the Annelides andthe Crustacea. 
+ Communicated by the Scientific Editor of Harfer’s Weekly. 
