GENERAL NOTES. 
Ins. 119 
0. S. Wilson has commenced a work entitled, “ The latvse of the British 
Lepidoptera and their food-plants, with life-sized figures, drawn and 
coloured from nature by Eleanora Wilson.” (Part i. 1877 : London, 
8vo, pp. xvii.-xxix. 48, pis. i.-viii.) The work is intended to bring 
together reliable descriptions of all the known larvae of British Lepi- 
doptera, and a large number are figured. Doubleday’s arrangement is 
followed, and the first part extends from the Diurni to the Procridm. 
A. Weismann has published Part ii. of his “ Studien zur Descendenz- 
Theorie : Uber die letzten Ursachen der Transmutationen.” Leipzig : 
1876, pp. xxii. 336, 6 col. pis. The greater portion of the work is taken 
up with an investigation of the variation of the larvae of different species 
of Sphingidce, undertaken for the purpose of determining whether they 
are due to the operation of the recognized causes of variation. The 
various stages of many European larvae of Chmrocampa, DilepTiila. 
Smerinthus, Macroglossa, Pterogon, Sphinx, and Anceryx are discussed in 
great detail, and compared with those exotic species of which the larvae 
are known. The first result of his inquiries is that the different colours 
of these larvae in different stages are really derived from those of the 
parent species, and are not the result of varying external conditions 
acting upon the larva at successive stages of its existence. The latter 
case only happens exceptionally, in the later stages of such species as 
Choerocampa elpenor and porcellus, which resemble each other very closely 
when young. He then lays down the three following laws : — 
1. Development begins with the simplest form, and passes gradually 
into the more complex. 
2. New characters first appear in the last stage of Ontogenesis. 
3. These characters pass backwards into the earlier stages, and inter- 
fere with the former characters till they finally obliterate them. This 
accounts for the appearance of rudimentary characters in an early stage, 
which only become fully developed in a later pne. 
The author next proceeds to consider whether the pattern of larvae is 
ah initio a purely morphological character, developed by inward impulses ^ 
and by a vital principle determining its growth, or whether it is only due 
to the action of external influences on the organism ; and concludes that 
both factors must be taken into consideration. The larvae of all Sphinges 
which are dimorphic or polymorphic in their later stages, possess the 
same colour when young. The protective significance of the green and 
brown dimorphism of many larvae with reference to the habits of the 
various species which exhibit it, is also fully discussed ; and subsequently 
that of the lines. Stripes, and other markings of Lepidopterous larvae in 
general ; and more particularly in Sphingidoe. The larvae of the Sphin- 
gidce were originally unicolorous, and first assumed longitudinal dorsal 
lines, then oblique streaks, and subsequently eye-spots ; and alterations in 
their colour and pattern are originally due exclusively to the recog- 
nized factors of natural selection and correlation. 
It is subsequently shown that larvae and perfect insects vary indepen- 
dently of each other, and that in the majority of cases, the structure of 
the larva has but little connection with that of the perfect insect. These 
points are also disoussed in the most elaborate manner, with the result 
