In the absence of Mr. W. Roberts, who was prevented by illness from giving his paper on “The structure of the Blow-fly” the secretary took his place, and introduced what proved to be an interesting discussion, by reading some notes on the same subject, illustrating them by the exhibition of slides showing various portions of the blow-fly.

The aeration of the blood is provided for, not as in higher animals by lungs, but by a system of delicate branching tubes called trachea, diffused through every part of the insect, and opening outwards by means of tiny pores, known as spiracles. A portion of one of the compound eyes was shown, and its structure described. In the blow-fly there are two of these clusters, each consisting of about 2,000 little eyes, and having a facetted appearance externally.

A very fine preparation of the tongue or proboscis was also shown, and its beautiful structure described. The other parts of the insect exhibited were the ovipositor, antenna, wings and feet. The way in which the fly walks upon any surface even in opposition to the force of gravitation was a topic of discussion, some speakers being in favour of the theory that the fly clings by a process of suction, others that it is by the exudation of a sticky liquid, which is known to be present on the feet, and which gives to the insect, for the time being, the power to attach itself to anything it places its feet on – the writer of the paper leaning towards the opinion that a fly adheres by the two methods combined.

The paper was also illustrated by a carefully executed sketch of the insect by Mr. J.M. Kirk, and some photographs of the proboscis.