MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 43 



Thvatira-like noctiiid. may have very soon after their establishment become .split by divergent 

 evolutionary forces into two groups, one giving rise to the Syssphingiua and the other to the 

 Svmbombycina. As will be seen by our provisional, tentative, phylogenetic diagram, the more 

 primitive notodontians. i. e., those which at birth are armed with simple setiferous tubercles, 

 gave rise to the Sy.ssphingina. 



The other branch or group of NotodontidiC. in whit'h the larva on hatching is armed with 

 multisetose warts, gave rise through Ichthyura to the superfamily Symbombycina, which com- 

 prises the six families already mentioned. 



The Eurypterotidi« may have descended from the Apatelodinie. I have not recently studied 

 this group and follow the suggestions of Dyar. who states that Apatelodes torrefacta in its first 

 stages distinctlj' shows the wart characters of the Eurypterotidiv. 



In the case of the position assigned to the Liparidit (Lvmantriid;v) and Lasiocampidte. I 

 follow in the main the suggestions of Dyar, having at present nothing new to offer. 



From the statements of Grote, and my own observations on the nature and position of the 

 warts of the fi'eshly hatched larva of Bomhyx hiovi and an investigation of its later stages, also 

 from an examination of the fully grown larva and the pupa of EndromtH cersicolora. as well as 

 recent studies on B rdlnnKa jiiponlca ^ I have .satisfied myself that the superfamily Symbombycina 

 ends in a group of three specialized families, as represented in the diagram on page 40, which have 

 all apparently descended from some common type. All have multisetose warts in stage I, and 

 lose them after the first molt; all have a caudal horn, while the BrahmaMdw have thoracic and 

 hinder abdominal horns in stages Il-IV. The Endromidiv and Bombycidw appear to have 

 branched ofi' from a common stem-foi-m. which had four medio-cubital branches. The BombycidiV 

 underwent a process of degen'eration; losing a vein, the head becoming reduced in size, the 

 palpi nuich reduced or ab.sent, the maxillse completely lost, the wings narrow and the power of 

 flight weak, the frenulum absent, the legs being spurless. 



The most aberrant and specialized group is the Brahnuvida'. which we shall elsewhere treat 

 of at greater length. It /*■ to he ohserved that in these fa mil w» what an- tlie larval characters of 

 the last stage of hairy notodontians and the families directly related to thrnt have heen croivded 

 hack during the course of their phylogenetic evolution, and are confined to stage I as the result of 

 the atrophy of the mxdtisetose vxirts; the body after the first molt Ijecoming naked and the caudal 

 hump or horn becoming a conspicuous feature, though even this is lost in the final molt of Brah- 

 mtea. It is interesting to observe in the ontogeny of Brahuiiva japonica that before the first 

 molt, besides the ordinary multisetose warts those, of the secotid and third thoracic and the eighth 

 and tenth abdominal segments are greatly elongated and hypertrophied, with the fine spinulose 

 slender .sette scattered along the trunk and at the end. These horn-like processes are, however, 

 discarded at the last ecdysis, when the body becomes naked, with mere vestiges of the " horns " left 

 to tell the tale of descent from some form more specialized in stage I than any other of the super- 

 family yet known. 



It should be observed of the families embraced in the Symbombycina. that they are all 

 Asiatic and African forms; i. e.. Arctoganc (chiefly inhabiting the oriental region) and Ethiopian. 

 The Apatelodina?. on the contrary, which we may provisionally regard as the stem form of the 

 Eurypterotidi\?, is American, the species all being confined to Central and North America, though 

 ^4. ardeola Druce ranges from Panama to the Amazons. 



It seems not improbable that the genus originated in Neoga-a. gradually passing northward 

 into the eastern ]\Iexicaii and Atlantic regions of Arctoga^a. Whether the ultimate origin of 

 such a great family as the oriental one of the Eupterotidie was in South America seems some- 

 what problematical. 



Origin of the superfiiii'tly Sysxjihingina. — The proofs of the more or less direct origin of 

 the Ceratocampid;e. and especially the genera Adelocephala and Syssphinx from the more primi- 

 tive Notodontidie; i. e. . those with larval uni.setose tubercles, .seems very strong. The affinities 

 of the larva? of the two groups are seen in the shape of the Ik^kI. the long h^gh epicranium, nar- 

 rowing towards the vertex, the great length of the median suture of the epicranium, and the 



