174 
specimen .was taken in May, and spring seems to be the season 
in which it usually occurs, though the present one was taken in 
the autumn. 
The best description of this insect is in De Geer’s valuable 
‘‘ Histoire des Insectes,” published in 1775.* He describes and 
figures both sexes; the figures, though uncoloured, being very 
correct representations. In reference to size, he says it varies 
very much, but he makes no mention of any individuals coming 
up to the size of the Bath specimen. The females are larger 
than the males, but with shorter antenne—not exceeding the 
length of the body. He describes the antenne as consisting of 
eleven articulations, which are always the same in number, what- 
ever be the length of the antenne: when the latter, therefore, 
are very long it is due to the lengthening of each articulation, 
and not to additional articulations. The antenne taper from the 
base to the apex, where they finish in a fine point. The eyes 
form a crescent surrounding the base of the antennez. The tarsi 
consist of four joints, much dilated in the males, and are furnished 
beneath with pads. 
De Geer has given a very particular account of a remarkable 
apparatus contained within the terminal segment of the abdomen 
of the female. This segment is very long and conical, but 
flattened above, having at the extremity a cleft, by which it is 
divided into two laminze—one above and the other below. From 
this cleft is exserted a long tube, black, cylindrical and fleshy. 
In the ordinary state of repose, or when the insect is walking, 
there only appears externally a very small portion of this tube, 
but by strong pressure on the abdomen the tube is forced to 
show itself, and gets more and more lengthened as the pressure 
increases. It is then seen that, in the process of lengthening, it 
comes out as it were from itself, in the same way as do the horns 
of a snail. Under continued pressure there is a bending of the 
* Tome v., p. 66. PI. iv., figs. 1 and 2. 
