Butterflies and moths (British) / by W. Furneaux.

  • Furneaux, William S.
Date:
1894
Catalogue details

Licence: Public Domain Mark

Credit: Butterflies and moths (British) / by W. Furneaux. Source: Wellcome Collection.

    29/408 (page 7)
    the proboscis is not a single tube, but, although so remarkably thin, is really a set of three distinct pipes, one lying on each side of the central one. It is said that the central tube only is used for suck- ing up the liquid food, and there seems to be some doubt as to the uses of the other two. Some naturalists are of opinion that the latter are air tubes, and are connected with the respiration of the insect; while others say that through these the insects eject a thin watery fluid with which to dissolve or dilute those sweetmeats that are not sufficiently liquid to be readily sucked up. But possi- bly both these opinions are correct, the proboscis serving all three of the purposes here named. The only observation of my own bearing on the subject is this. While a moth was feeding on a drop of syrup in a strong light, a powerful lens revealed drops of liquid, mingled with bubbles of air, passing alternately up and down the two lateral tubes of the proboscis. At the same time the upward current of syrup in the central tube was by no means steady and continuous. When this organ is not in use, it is beautifully coiled into a close spiral which lies between the labial palpi. The length varies considerably in different insects, and consequently the number of turns in the spiral must differ also. Sometimes there are less than two turns, while some of the longer ones form spirals of from six to ten turns. In concluding our brief account of the head of lepidopterous insects it is, I suppose, hardly necessary to add that there is no kind of chewing apparatus to be described ; all the members of this order, at least in the perfect state, deriving the whole of the little nourishment they require entirely by suction through the proboscis or ‘ trunk.’ The second division of the body is the thorax. This is much larger than the head, and consists of three ring-like segments, joined one behind the other so intimately that the lines of junction are hardly visible, even after the thick clothing of tine hair has been brushed off. Behind the thorax is the abdomen, which is composed of several segments, the junctions between the rings often being most distinct. From the sides of the thorax proceed the two pairs of wings, the general structure ot which we have already to a certain extent examined. But when we are a little farther advanced in our Fig. 7.— Section of THE PllO- BOSCIS OF A Butterfly.