194 NATURAL HISTORY OF WASPS. 
to work at, but that they all worked anywhere and 
anyhow. And this, whether they were engaged in 
adding to the structure, or in removing what had 
been built previously. So, a wasp which had been 
collecting white fibres joined her quota to what had 
been built by a wasp which had gathered materials 
of a darker colour, giving a variegated appearance 
to the work. Further, it seemed clear that only the 
young wasps built, probably because they only had 
the power of secreting mucus in sufficient quantity 
for working up the dry fibres into a pulp. This was 
inferred from the generally larger size, and the 
smooth ends of the wings, of the wasps which were 
examined while thus engaged. Wasps grow smaller 
as they grow older, and the ends of their wings get 
tattered with advancing days. : 
Marking a wasp is an operation requiring a little 
skill. Pastor Miiller* used to put a little colour on 
the antenne of his tame hornets; but this plan 
admits of very little variety in the marks. First 
catch your wasp. Réaumurt used to catch his by 
means of a stick tipped with some glutinous matter ; 
but to this mode of proceeding there are obvious 
objections, particularly on the part of the wasp. I 
prefer a glass tube, about twelve inches long by 
three-eighths of an inch wide. This should be joined, 
by a piece of India-rubber tubing, to a mouth-piece, 
and be stopped at this end by a few turns of fine 
wire, loosely packed, so as to let the air pass freely, 
but to catch the wasp as it is drawn in. With this 
* Miiller, ‘ Beitrige zur Naturgeschicte der grossen Hornisse,’ op. 
sup. cit. 
+ Réaumur. ‘Memoires pour servir 4 I’Histoire des Insectes.’ 
