NOTODONTID.E. Introduction. By Dr. A. Settz. 283 



of Pygaera anastomosis, whereas on the otlier trees of the group only single specimens were observed and these 

 were evidently accidentally dispersed. 



Owing to their preference for the higher trees in woods and avenues the Notodontidae are not inju- 

 rious to agriculture and also not actually dangerous to forests. Real defoliation has been observed by me only 

 in the case of Lime, Willow and Poplar, trees which all suffer extraordinarily little from the lo.ss of the foliage. 

 The Notodonts do not occur in such numbers that they can defoliate forests or whole nurseries, although we 

 may meet with them very frequently in nature. As in the case of the distribution of the family, which will again 

 be considered later on, also the yearly number of individuals is uncommonly constant, which accounts for the 

 special role which the Prominents play in the fauna. It is quite surprising how constant is the abundance 

 or rarity of the Notodontidae year after year in the various localities. Such an enormous difference in the 

 abundance of specimens as is sometimes observed in certam other Lepidoptera, as e. g. in Dendrolimus pini, 

 Lymantria dispar etc., which disappear sometimes for years and then again occur in incredibly large num- 

 bers, is entirely unknown among the Notodontids. 



When we said above that most of our European Prominents are common species, either actually being 

 found in numbers or appearing less frequently in collections because their home is difficult to reach, we 

 did not mean to maintain that there are no great rarities here and there among them, species which either 

 are on the verge of extinction or whose centre of distribution has not yet been discovered. I mention Py- 

 gaera timon, for instance, which is still very rare in collections, further Rhegmatophikt alpina, whicli has a very 

 small area of distribution, being restricted to the neighbourhood of Digne, and Cerura verbasci, which has 

 nowadays almost disappeared from the dealers' lists. The strikingly marked Uropyia meticulodina from 

 Eastern Asia is almost exclusively obtained by breeding, and the robust Nadata cristata, which has the facies 

 of a Lasiocamp, is a rare catch at the lamp. 



Most of the Notodonts have two broods in the temperate countries. The genera Cerura, Pheosia, 

 Notodonta, Pygaera, Pterostoma, Lophopteryx, and Drymonia, some of which contain a considerable number of 

 species, usually appear in the early spring and again late in the summer. A number of other genera have a so-call- 

 ed incomplete summer brood, e. g. Stauropus fagi, some of whose offspring appear as moths in the autumn of 

 the same year, while the greater porportion of the pupae hibernate. 



In a very small number of other genera the duration of the pupal stage does not appear to be'ever 

 shortened, or only exceptionally so, as for instance in most Phalera. Seasonal dimorphism has not been 

 observed in the double-brooded species, with the exception of Pygaera ajncalis, whose spring and summer 

 broods have been proved by Betjtenmuller to show a noteworthy difference. 



The Notodonts are rather constant not only in the succeeding broods but also in the different districts. 

 Only in certain areas of America did Packard believe to have observed local variation with a tendency 

 towards melanism, but the did not consider the occurrence of the phenomenon established on suffficient evi- 

 dence. In the Palearctic Region a darkening of the ground-colour is sometimes observed m the North 

 (Dicr. phantofna), sometimes in the South (Dicr. delavoiei), and m other cases also in the East {Hoplitis 

 umhrosa, Gluphisia amurensis). But the variation is on the whole so insignificant that the family must be 

 considered one of the most constant. 



The geographical distribution is very uniform. In the local faunae of Central Europe almost every- 

 where about 30 species of Prominents may be considered as indigenous, and in the whole Palearctic Region about 

 200 forms have been observed. In Northern Africa occur about 80 forms. South America, India and Africa 

 have each 100 — 200 forms. The Australian Continent is decidedly poor, hardly a dozen species having been 

 found; but some of these are very large, and the number will certainly increase as the exploration of Au- 

 stralia, especially the tropical northern districts, proceeds. 



The variety exhibited in the facies of the Notodontidae is to some extent repeated in the details of the 

 structure of their bodies and wings, so that we can give but few'morphological characters which apply to the 

 entire family. Moreover, an exact delimitation of the family is still wanting. 



Head large, anteriorly quadrangular, covered with dense woolly hair, frons broad, between the antennae 

 sometimes a crest of hair, and above the base of the antenna short tufts; capsule of head without groove 

 for the reception of the shaft of the antenna at rest; occiput very short behind eyes and antennae. An- 

 tenna usually of normal length (about ^o the costa); always pectinate in (J, sometimes to the tip, sometimes 

 to two-thirds, the branches in some forms (Datana) long and characteristic in shape, or spread out [Birda plu- 

 mosa). Maxillae well-developed, the proboscis functionless, only said to be large in Tarsolepis, in the other 

 Notodonts obsolescent. Palpi sometimes short, sometimes long, strongly hairy, sometimes abnormally long 

 (Pterostoma). Thorax robust, broader than long, the prothorax very short, mesothorax transverse, meta- 

 thorax above very narrow. The forewing narrow, elongate, with the costal margin straight or slightly con- 

 vex, and the distal margin very oblique, usually entire, rarely dentate; the hind margin bears very commonly 

 a tooth-like jirojection which is densely covered with hair-scales ; the subcostal 5-branched, remaining close 

 to the costal margin to the apex; the cell usually long and narrow, gradually increasing in width, middle me- 

 dian branch (vein 5) nearer to the upper than the lower angle. The hindwing rather small, ovate, as a 

 rule far surpassed in length by the abdomen; costal edge straight, apex more rounded than is usually the case 



