312 Professor E. B. Poulton on colowr-relation 
the experiment on this and other suitable larvze on the 
first opportunity. 
I propose to state the results of these experiments 
forthwith, referring to the plates which accompany the 
paper. Hence it will be possible to gather the conclusions 
by looking at the few first pages, while those who desire 
to study the evidence in detail will find it recorded in the 
later part of the memoir. 
The first larva which appeared suitable for the purpose 
was Odontopera bidentata, and Mr. G. 'T. Porritt very kindly 
consented to look out for eggs. Mr. Porritt had himself 
suggested to me that the larva would probably prove to 
be especially suitable for the purpose of this enquiry, and 
he wrote on May 9th, “the larva varies so very much in a 
wild state according to its food, that I fancy it will form an 
interesting subject for your experiments.” * On May 9th, 
1893, he kindly sent me from Huddersfield a batch laid by a 
single female, and, on June 13th, asecond consignment laid 
by two females, from Sledmere on the Yorkshire Wolds. 
The first set afforded the material of Experiments I to IX 
(including VA) described in this paper. The second mixed 
set formed the subject of Experiments X to XVIII. 
The chief results of both experiments will be gathered by 
a glance at Plate XVI, in which figs. 1 to 5 represent 
larvee from the first set of eggs, figs. 6 to 11 larvae from the 
second set. At the same time results like those shown in 
the former figures were produced in larvze of the second set 
and like those in the latter figures, in larvee of the first set. 
The detailed account of the experiments shows the 
number of days which elapsed before the influence of each 
environment became visible, and the time which was 
necessary in order to produce the full effect. A very large 
number of records proves that the larvee, in the great 
majority of cases, rested by day upon the object which 
* Dr. T. A. Chapman wrote to me (June 14, 1903), concerning the 
forms and habits of bidentata :—‘‘ About forty years ago, I took 
three or four beautifully green latticed larvee off the lichen-covered 
trunk of an old alder-tree in Glen Messen (Argyleshire). They 
were quite new to me, and though very like (of course) bidentata, 
I thought they must be something else, a lichen-feeder. When they 
produced bidentata, I got no further than wondering whether bidentata 
was sometimes a lichen-feeder. I remember well their resting-place 
was near the ground, many feet from any leaves,—as long a journey 
for feeding as the larva of Aprilina makes.” 
