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The New Zealand Railways Magazine, Volume 6, Issue 5 (November 2, 1931)

The Silver Fish

The Silver Fish.

There is a small insect, about one-quarter of an inch in length, well known to most people, and whose presence is greatly resented by them. In fact, so great is this feeling of resentment, so deeply rooted, that all possible means for getting rid of the insect's presence and attentions are made use of. It is the bete noir of the careful and thrifty housewife owing to its marked predilection for starched articles of wear such as collars, shirts, curtains and the like; this, strangely enough, when we consider that sugar is the insect's main diet; this will be explained later on. At times this deep aversion is carried to extremes, and, to quote an authentic case in point, one that ended in an action-at-law, to a ridiculous degree.

A “flat” was rented by a tenant, who, on entering into occupancy, found the premises infested with these creatures. So alarmed was he at the discovery, that he got out and went back on his agreements in refusing to pay any rental.

This pest appears to be ubiquitous in habitat, being prevalent in all parts of the world. How it came by the name of “silver fish” is difficult even of conjecture, as the insect does not possess a single “fishy” attribute.

The best known variety, generally, is the “silver fish,” Lepisma Saccharina (figure 2), which confines itself to “homes,” and is, in consequence, most frequently met with. It has many aliases—I use the term as it is a silent worker and non-advertiser—“Bristle tail,” sugar louse,” “sugar fish” and “silver witch.” Of these “sugar louse” and “sugar fish” seem the most appropriate from the dietary—“sugar.” This is procured in a round-about or second-hand fashion, from the underneath of linoleum, the back of wall papers, book-bindings, and starched clothes that are put away in drawers and dark places. There is enough “sugar” contained in the above-mentioned articles to suffice the insects' need; and it is owing to this method of obtaining their staple food supply that we consider them destructive enough to class as very undesirable, something to be destroyed or got rid of.

Another variety, not so well known, is the “fire bratt” (Thermobia Funorum), that infests bakehouses and ovens, and have received their name—again erroneous—from bakers. These greatly resemble Lepisma, and procure their “sugar” from flour, dough and paste.

These little creatures belong to a most primitive and interesting form, Thysanura, from which most of the world's insects have “evolved.” The mouth is most simple, as is also the breathing system; the body minutely and entirely scaled, giving the insect a soft silky and silvery appearance. Wings are completely absent, while the bristle-like objects at the tail are to be found in the lower insect types; in higher types these are developed into forceps.

The three forms touched upon in this article are Lepisma Saccharina, Thermobia Funorum, nd Campodea Staphylinus.” Of all these, Lepisma is certainly the most advanced.

The “scales” of Lepisma (figure 2) achieved fame for these insects; for, to meet the requirements of examination, the lenses of to-day's microscope were brought to their present perfection. As in moths and butterflies, these scales are of a hairlike formation, the surfaces broken up by lines and ridges from which the light-rays are turned, giving the bearer its metallic silver gloss.

The “fire bratt” (Thermobia Funorum) has already been sufficiently mentioned.

We now come to Campodea Staphylinus (figure 1), the most important and primitive member of the group, and fairly common throughout the globe. It lives in decaying and moist wood, under stones, in fact, whereever page 64
(Figure 1.) Campodea Staphylinus (Most primitive of all insects.) (Figure 2.) Silver Fish (Lepisma Saccharina.)

(Figure 1.) Campodea Staphylinus (Most primitive of all insects.)
(Figure 2.) Silver Fish (Lepisma Saccharina.)

the ground is soft and damp. Very little is known to entomology of this strange creature; this, no doubt, is to be accounted for owing to the extreme fragility of its body construction. So great is this peculiarity indeed that to even touch one with the fingers is to destroy it completely. In order to emphasise more thoroughly this fact it may be mentioned that to procure a specimen, even with the aid of a soft camel-hair paint brush, without shattering, is well nigh impossible. Again, even if this may have been accomplished, death occurs very soon after capture. The body cannot be kept for “dried specimen” purposes even though it will provide a “microscopic” preparation.

These fragile insects have no organ of sight, and may, therefore, be deemed blind; they entirely avoid and shun light of any description, and their delicate bodies are soft and white; the breathing tubes simpler even than those of Lepisma. Yet, in spite of this extreme fragility, they flourish and multiply where “higher” insects of hardier form die out or become extinct.