One remarkable point in these Hymenopteroid Syntomids is their complete dissimilarity from their immediate allies. They resemble very different Hymenoptera; and not only stinging Hymenoptera; the Sessiliventres have a large share of their attentions; the numerous species of Dycladia partaking the appearance of the South American Sawflies in a wonderful manner. Bees, Wasps of the most different kinds, and a variety of Sawflies are beautifully paralleled, if one may use such an expression, by these Syntomids. That shown in Fig. 194 has the abdomen formed like that of a Petiolate Hymenopteron; the base of this part, moreover, resembles in a remarkable manner the "median segment" of that Order. The constriction is, however, placed not at the base of the abdomen but beyond the second segment. Thus the structure is not morphologically similar to that of the Hymenoptera, for the median segment of Aculeate Hymenoptera consists of only one abdominal segment, while in this moth the corresponding part is formed of two segments. Though anatomically inexact, the resemblance is, as to proportions, correct; and those who delight in the use of the imagination will see that had the moth used only one segment for the imitation, the result would have been less successful owing to insufficient size. In his very interesting account of some Brazilian Syntomids,[[274]] Seitz describes a species of Trichura provided with a long appendage that is held straight backwards during life; and he informs us that this creature resembles a female Ichneumon, the long process looking like the elongate ovipositor of the Hymenopteron. Possibly the species from Demerara we figure may resemble an Ichneumon we are not acquainted with, though its colour and form rather suggest a likeness to an Aculeate. This case of resemblance is of the most noteworthy character, for an appendage of this kind in a Lepidopterous Insect is without parallel, and is almost equivalent to the production of a new structure. An interesting feature of the case is that Ichneumonidae do not sting, and there is no evident reason why the enemies of the moth should be particularly afraid of an ovipositor.
The larvae appear to be in form somewhat like those of Zygaenidae; but with the same sort of remarkable clothing, in the form of tufts and brushes, that we find in Lymantriidae. A cocoon is formed. In Britain no member of this family is to be met with, but Naclia ancilla may formerly have been a native; Syntomis phegea has occurred here; probably an escaped example that had been introduced in one of its earlier stages.
Fig. 194—Trichura, sp. × 2⁄1. Demerara.
Fam. 16. Zygaenidae (Burnet-Moths).—This family is one about the limits and characters of which much difference of opinion prevails. As exemplified by our Burnet-moths it is characterised (in addition to the points given in the table) by the peculiar, flexible antennae; these are a little thicker before the tip, but are curved and pointed at the extremity, and without pectinations in the male. There is an elongate proboscis; bladder-like organs at the sides of the first abdominal segment are not present. The pupa is softer than is usual in the Macrolepidoptera, and the parts are less firmly fixed together, so that unusual mobility exists; six of the intersegmental membranes are free, and the abdomen has much power of movement; there is no eye-collar; the antennae, hind legs, and proboscis-tips stretch backwards as far as the fifth or sixth abdominal segment, the tips being quite free; on the dorsal plates of the abdomen there are rows of minute elevations reminding one of the teeth existing in pupae that live in stems or galleries. This is altogether a peculiar pupa; it lives closely enclosed in a small hard cocoon, and its great capacity for movement is perhaps connected with the fact that the pupa itself manages to force its way through the cocoon in anticipation of the emergence of the moth. This cocoon is fastened tightly to a stem, and is covered with a substance that gives it a glazed appearance. The larvae are objects of a baggy nature, with inferior coloration, consisting of large dark blotches on a light ground, and without any remarkable development of their somewhat feeble system of hairs. Numerous small moths from the tropics are assigned to the family; they are most of them conspicuously marked and coloured, and like our Burnets are probably diurnal.
Fig. 195—Hampsonia pulcherrima. Wings on right side detached and denuded to show nervuration. India. (After Swinhoe.)
The family Chalcosiidae is reduced by Hampson to the position of a sub-family of Zygaenidae. It consists of a large variety of diurnal moths of varied and brilliant colours, with an expanse of wing large in comparison with the typical Zygaenae, and with the antennae pectinate or flabellate to the tip. Some of these Insects (which are as conspicuous as possible in appearance, at any rate in a cabinet, the East Indian Cadphises moorei e.g.) are considered to be destitute of any special "protection." Histia is a genus of remarkable cruciform moths, of a mixture of black and metallic colours, with carmine-tinted bodies. Hampsonia pulcherrima (East India) is a curious moth of butterfly form and coloration, red and black with yellow patches, and with some of the nervules distorted, as if they had been forced apart in certain spots in order to accommodate these patches.
Two or three hundred species of Chalcosiidae are recorded. They are specially characteristic of the Indo-Malayan region.
Fam. 17. Himantopteridae (Thymaridae of some authorities) are placed by Hampson in the sub-family Phaudinae of Zygaenidae characterised by the absence of the mouth-parts. The Himantopteridae are small moths, and have the scales on the wings very imperfect and hair-like; the hind wings form long slender tails, so that the Insects scarcely look like moths. They are peculiar to India and Africa. In the South African genus Dianeura (belonging really to Phaudinae) also the wings are scaleless and nearly transparent.