380 BRITISH LEPIDOPTERA. 



washed, the pink is restored, and the yellow entirely removed. 

 The colour has, however, a faded appearance which is maintained, 

 the pink colour being dull, but the red is quite permanent (Coste). 



Girard says (Cosmos, xvii., p. 282, and Bull. Soc. Ent. Fr., i860, 

 pp. lxxxv — lxxxvi) that the secretions which enable certain species 

 to emit a scent resembling musk seem to offer in some measure 

 a generic character or evidence of affinity. He has frequently 

 observed it in ^s of Agrius convolvuli, as already remarked by 

 previous authors, though never in the $ , and has also detected it in 

 Sphinx ligustri, though less powerfully. He thinks it would be of 

 interest to examine the third species of the genus, Hyloicus pinastri, so that, 

 if this, too, possesses it, it might be added to the generic characters. 

 In 188c, Von Richenau recorded (Kosmos, iv., p. 387) that both 

 Sphinx ligustri and Hyloicus pinastri were provided with a special 

 scent-organ situated at the edge of the lower side of the 1st abdominal 

 segment, which comes into view on pressure of the abdomen. It 

 consists of two symmetrical bunches of hair-shaped scales, which may 

 be extruded or drawn in. When extruded in a living S. ligustri a distinct 

 musky scent is apparent at the distance of half-a-metre, but ceases 

 to be apparent when they are retracted into their fold, which occurs 

 when the insect is at rest. Only a rudiment of this organ is 

 present in the 2 . 



Green notes ( E.M.M., xxxvii., p. 90) that Hippotion celerio was 

 found to make a squeaking noise, much like the well-known note of 

 Manduca. The peculiar noise made by Manduca atropos will be 

 dealt with at length later. 



Cross-pairing has been recorded between Hyloicus pinastri $ 

 and Mimas tiliae 2 (Bartel, Palaeark. Gross-Schmett., ii., p. 148) ; 

 Treitschke fnotes Die Schmett., x., 1, pp. 137 — 138) the pairing of 

 Smerinthus ocellata $ with Hyloicus pinastri 2 , and Herfert 

 (Insekten-Borse, xvi., p. 280) observed a $ S. ocellata paired with 

 a 2 M. tiliae at Linz. Although cross-pairings such as the two 

 first-named are almost sure to prove abortive, experience 

 has since shown that the last-named (though with the sexes 

 reversed) may be quite fruitful. Successful cross -pairing, how- 

 ever, is not at all infrequent among Sphingids, and it is many 

 years since the successful crossing of Smerinthus ocellata $ 

 with Amorpha populi 2 was first recorded, the product being named 

 hybridus by Stephens (List Br. An. Br. Mus., p. 26), although it 

 had been figured by Humphreys and Westwood some years pre- 

 viously. Hagen notes ( Ent. IVk. Int., iv., p. 23) that Miitzell had 

 described in Wiegmann's Archiv, under the name of phileuphorbiac, 

 a hybrid between euphorbiae and gallii, but this has since been 

 queried as being simply an aberration of the latter species, whilst 

 vespertiloides has been suggested as a hybrid between vcspertilio and 

 gallii or euphorbiae. The following are the only hybrids to which we 

 have yet found reference in entomological literature : Smerinthus 

 hybr. hybridus, Stephs. (ocellata $ X populi 2 ), Amorpha hybr. 

 inversa, Tutt (populi $ X ocellata 2 ), Calasymbolus hybr. interfaunus, 

 Neum. (astylus $ X ocellata 2 ), Smerinthus hybr. fringsi, Stdfss. 

 (atlanticus $ X populi 2 ), S. hybr. oberthilri, Tutt (atlanticus 

 S X austauti 2 ), A. hybr. metis, Aust. (austauti $ X 

 atlanticus 2 ), Mimas hybr. leonine, Stdfss. (tiliae $ X ocellata 2 )■> 



