56 



BRITISH LEPIDOPTERA. 



enables them, as we have already noted, often to travel great 

 distances from their home into our own regions as immigrants. 

 Bartel further points out that the Palaearctic Phryxid species 

 belong for the most part to the southern and eastern portions of the 

 region, and that some species, such as Phryxus livornica, Hippotion 

 celerio and Daphnis nerii, of which the two last-named probably 

 originated in the Ethiopian region, are only seen in the more tem- 

 perate parts of the district in very warm and favourable seasons as immi- 

 grants. In such years they spread a considerable distance north, lay 

 their eggs, the autumnal larvae and pupae being killed off under the 

 more stringent climatic conditions to which they are subjected, and the 

 species are not then seen again for some time. Some of our European 

 species, Daphnis nerii, Phryxns livoniica, Hippotion celerio, hoples 

 alecto, I. boisduvalii occur also in the Indo-Australian region, the 

 three first-named and Thaumas ?nauretanica also in Africa. Celerio 

 gallii is also recorded from Labrador and the United States, but the 

 specific identity of the American and European examples is open to 

 some doubt, whilst Phryxus livorniea is represented in North 

 America by the nearly allied representative species, P. lineata. 



Tribe : Eumorphidi. 

 Our tribe Eumorphidi comprises many of the species that were 

 formerly known as the Chcerocampids, a name given to them 

 on account of the formation of the three thoracic segments and 

 head, which form a sort of snout, and are more or less retractile 

 within the swollen ist and 2nd abdominal segments. The only 

 really sedentary species — porcellus, elpenor — found in Britain, be- 

 longing to the Eumorphinac, are members of this tribe. The eggs 

 are of the typical Sphingid form and colour, small for the size of the 

 moth, but apparently with no especial characteristics. The larvae 

 exhibit many minute differences when compared with those of 

 the Phryxids, their nearest allies. In tabulated form these differences 

 work out as follows : 



EUMORPHID LARVA. 



PHRYXID LARVA. 



1. Tubercles iv and v separate on ist 



abdominal segment. 



2. Caudal horn small (or aborted) in later 



stadia. 



3. Thoracic segments retractile into tumid 



1st and 2nd abdominal segments. 



4. Ocellated spots developed from sub- 



dorsal band on 1st and 2nd (and 

 possibly other) abdominal segments. 



5. Conjoined subsegments 1 — 3 of ab- 



dominal segments not specially 

 marked in adult (i.e., the character 

 is waning). 

 (y. Pigment spots at the base of the 

 shagreen (or secondary) hairs not 

 speeially developed. 



iv and v conjoined on 1st abdominal (in 

 euphorbiae) [? a generic or specific 

 character]. 



Caudal horn retained throughout all the 

 stadia. 



Thoracic segments not retractile ; ab- 

 dominal segments 1 and 2 not tumid. 



No ocellated spots on special segments, 

 but a chain of bright spots usually 

 developed irom subdorsal band on 

 most (or all) of the segments. 



Conjoined subsegments 1 — 3 of abdominal 

 segments a marked feature of adult 

 larva li.c, the character is not 

 waning). 



Pigment spots strongly developed at the 

 base of the shagreen (or secondary) 

 hairs. 



Weismann has treated (Studies in Theory of Descent, pp. 177-199) 

 this group of larvae at considerable length, but we cannot do more than 



