followed this example in the direction of writing on all 
the groups of the animal kingdom with his own pen, but 
has been fortunate in getting together a number of con- 
tributors, whose very names command respect for their 
contributions. The table of contents of the just published 
volume shows that the subjects of the Insects, Myriopods, 
and Arachnids have been written by Mr. W. S. Dallas, 
with the exception of the Lepidopterous Insects written 
about by Mr. W. F. Kirby, the Crustacea are described by 
Mr. Henry Woodward, the Echinoderms by Mr. Herbert 
Carpenter, the Sponges by Prof. Sollas, the Rhizopods 
by Prof. Rupert Jones, and the Worms, Zoophytes, and 
Infusoria by the Editor. 
We have been greatly struck by the immense amount of 
information given to us by Mr. Kirby in Chapter IX., which 
treats of the characteristics of the order of Lepidoptera, 
gives an account of the evolution of these insects from 
the egg to the perfect state; describes the imago con- 
dition ; gives a condensed but very clear account of their 
anatomy, food, and geographical distribution, and con- 
NATURE 
[ Fred. 15, 1883 
and 40,000 moths; but then Mr. Kirby adds: ‘‘ Hun- 
dreds of new species are being added to our lists every 
year.” The abundance of species in a district would 
seem to be in proportion to the variety of the vegetation, 
which latter is intimately connected with variety of ele- 
vation, and so it is ‘‘that Lepidoptera are far more 
numerous in Switzerland than in the peninsulas of Italy 
and Spain :” but is it not possible that the mountainous 
regions of Spain will still yield many as yet unknown 
forms? The illustrations in this portion of the volume are 
often very beautiful, and comparatively new. Of the next 
order, Diptera, says Mr. Dallas, “it is not easy to arrive 
at any trustworthy estimate of the total number of species, 
yet allowing Dr. Schiner’s estimate of 9000 species as 
European, it has been calculated that the total fly popu- 
lation of the world would be from 150,000 to 160,000, 
Only a very few of this great army could be of course 
| alluded to, but the information given about the gnats, 
cludes with a few hints on collecting, killing, and setting. | 
Among the statistics of lepidopterous life, we note that 
the present census gives about 10,000 species of butterflies, | 
midgets and crane flies is very full and interesting. Many 
of these forms are injurious to our crops, as well as irri- 
tating to ourselves. The Gall Midges (Cecidomyidz) are 
among the most delicate species of all these gnat-like 
Diptera. 
The larvee of these elegant little insects feed 
Fic. 1.—Cecidomyid with viviparous larva. 
upon various species of plants. The number of species 
is very considerable, about 100 being recorded as Euro- 
pean. Many of them by attacking useful plants, fre- 
quently do much mischief. Among these may be men- 
tioned the Hessian Fly (Cecidomyia destructor), which 
has done so much damage to the grain crops of the United 
States, and which received its name from a belief that it 
was introduced into the States with the baggage brought 
by the Hessian troops in the pay of the British Govern- 
ment about the year 1776. The Wheat Midge (C. ¢riticz) 
is an enemy of the wheat crops in this country, some- 
times doing much damage; several other species form 
the flower-like galls oftentimes found on willows. 
In 1860 Dr. Nicolas Wagner, of Kasan, made the 
startling discovery that in certain of these Cecidomyids 
the larval stages could give rise by a kind of budding, to 
several small larval-like forms, and that when these latter 
got free, they in their turn produced still other larval forms 
in the same curious fashion, and so one generation 
succeeds another throughout the autumn, winter, and 
spring. Inthe summer the last generation undergoes a 
change to the pupa state, and from these pupe the 
A, adult insect; B, B, pupz ; C, larva, showing young larve at aa, 
perfect winged males and females emerge. The latter 
lay eggs in the bark of trees, and the larve produced from 
these commence once more a fresh series of organic 
broods. This strange circle of development is in part 
represented in the accompanying illustration, which will 
serve as a fair example of those which abound in this 
volume. Al] the families of the flies, ending with that of 
the flea, which, however, is placed in an order by itself, 
are well and judiciously treated. 
The chapter on the Rynchota is also, despite its sub- 
ject, a very interesting one, and a great deal of useful 
information is crowded into a small space. Mentioning 
the noise produced by the male Cicada, the author says : 
“During the heat of the day they sit concealed amongst 
the foliage of the trees and shrubs, and sing incessantly ;” 
but is it not rather their wont to select the end of some 
dead twig, or the extremity of some vine pole, and there 
out in the full glare vibrate violently. A little space might 
have been spared for an account or figure of the vine 
phylloxera. 
The chapter on the Orthoptera begins with the crickets 
and ends with the springtails. Among the Myriopods 
