418 DUOMITUS; COSSUS. By Dr. A. Seitz. 



1. Genus: ]>iioiiiitiis Butl. 



This genus, consisting of about two dozen species, some of them gigantic, is distributed over all parts 

 of the globe excepting Europe. They are certainly not only the largest but also the most typical representa- 

 tives of the C'ossid family; true wood-borers, with naked larvae resembling those of beetles. The caterpillars 

 have enormous pincer-like mandibles, avoid the light, are long lived, massive in the dimensions of their body, 

 and primitive in structure. Their exoskeleton is soft and elastic, as long as the sheltering walls of the tunnels 

 in the wood protect the larva from external injuries, but becomes hard, a kind of armour, as soon as the insect 

 emerges into the open air. 



Head comparatively small; frons narrow, less than half as broad as the large and very prominent 

 naked eyes. The palpi very small, horizontal, only the small cap-like end-segment projecting above the eyes. 

 Tongue entirely absent as in nearly all Cossids. Vertex with shaggy broad tuft of hair, which is, however, 

 only present in fresh specimens. Thorax robust, downy hair broadened into scales at the ends on the pro- 

 thorax and patagia and on the basal segment of the abdomen. Antenna of 2 simple, bipectinate in the ^J, with very 

 long teeth in the basal half, apical half filiform. Legs of medium length, stout, without distinct spurs, but with 

 strong apical claws, with which the insects can scratch as energetically as many beetles. Wings thick, coriaceous, 

 in the (J resembling those of the Sphingids in shape, in the 9 moderately broad with curved hind margin; wood 

 colour, with light patches recalling lichens and markings resembling the grain of wood. Abdomen of (J slender, 

 of $ heavy with the ovipositor capable of being extended 1 cm, back of abdomen clothed with felty hair. 



Among all the Continents Australia mth its primitive Lepidoptera has the largest number of species 

 of Duomitus, the gigantic D. Uturahis Don. and its allies being especially striking. The larvae live in the trunks 

 of the great forest-trees, especially in the juicy species of Ficus, and often do a great deal of damage m timber. 

 The moths rest by day, with the wuigs folded close to the body; the prothoracical tufts, crest-like in the 

 live insect, and the anteriorh' truncate tuft on the frons. imitate a splmter of wood, the similarity being often 

 heightened by the white colour of the thorax resembling the end-surface. The moths fly late at night, and are 

 strongly attracted by light. Such a heavy moth dashing against the closed window of a block-cabin is apt 

 to startle the inhabitants, and specimens rushing about a room produce a rattling sound with their wings. 



The moths become rarer at the boundaries of their areas of distribution, and it is very difficult to tell 

 how many species enter the Palearctic Region. Three species probably extend across the southern boundary, 

 but only one species has as yet been caught on Palearctic territory. 



lettconotus. D. leuconotus Walk. (= persona le Guill.) (53 a). At once recognized by the white hairs broadened 



to small scales at the end. which clothe the thorax and back of the base of the abdomen. The wings are grey 

 with dark marbling, and with variable white spots at the hind and outer margins and apex. Distributed from 

 Kashmir over the whole Indian Empire to Ceylon, abundant nearly everywhere. ■ — Larva when half-grown 

 flesh-coloured, yellow anteriorly and posteriorly, with black spots behind the head. It bores in large numbers 

 in the trunks of Cassia nodosa, making tunnels up to 2 cm in diameter, and according to Skellixg over 30 were 

 found in the trunks of quite young trees. Pupa dark chestnut, almost black, with orange segmental incisions, 

 stigmata black edged with orange. In a cell of wood at the end of the tunnel. After 1 V^ to 2 months the pupa 

 pushes forward, and the moth emerges, which seems to fly particiilarly in March and September. The small 

 yellowsh brown eggs are deposited in clusters on the trunks, especially in crevices; the larva takes 2 years 

 to develop. The natives collect the insects on the tree-trunks as well as at the light, the insect coming to the 

 street lamps in the towns. 



The double prothoracical tuft completely covers and hides the head of a fresh specimen at rest, but 

 is often absent in worn $?. The natives call this insect French moth, a name whose derivation is unknown 

 to me; perhaps it refers to the colour French grey ( ?). The ^ varies considerably in size, and I sometimes 

 caught specimens Avhich were smaller than Herse convolvuli. 



2. Genii.s : Coi-isiis F. 



Still more widely distributed than the jireceding genus, as one species also extends over nearly the 

 whole of Europe, and even to the North of Scandinavia. The chief points of difference from the preceding 

 genus are its stout build, broader wings, the tibial spurs, which are present althoiigh slight, and especially 

 the antennae, which are uniformly serrate ($) or pectinate ((J) to the apex, while the antennae of the (J^J of 

 both Zeuzera and Duomitus have long pectinations in the basal half, but are naked and setiform distally. 

 It is as well to pomt out here that the antennae of Cossus have also been said to be the principal distinguish- 

 ing character between that genus and the following //o?cocer!<s, whose antennae ((3*) are only flat shafts without 

 real teeth or pectinations. But until the more mumte anatomical structure of these antennae has been examin- 

 ed, one cannot really speak of a generic distinction, as gradual differences in the pectmations of antennae 



