( :m ) 



LXXXV. PACHY8PHINX gen. nov.— Typns : mn>/^.<^f.a. 



Stnfrinthits, Harris (iitm Latreille. ISO'2). in Sillira.. Jnarn. Sri, Art xxxvi. p. 202 (1H3G). 

 Ldiithoc, Grote (nm, Fabricius, 1807). Dull. Biiffiih, Soc. N. Sri. i. p. 24 (1H74). 

 Aniorpha, id., I.e. ii. p. 227 (1874) (iinm. iiiiiL). 



Triptopon, Butler, Traiix. Znnl. Sue. Lmid. ix. p. hK^ (1877) {iiniii. nuit. ; partim). 

 Marumba, Kirby {mii Moore, 1882), Cat. Lep. Hit. i. p. 708 (18',I2). 



(??. Very close to S/j/itnx, frora which it differs, in the larcal state, in the 

 reduced horn, the slight)}' humped thoracical segments and less triangular head ; in 

 the imago state, in the liristlcs of the jiilifer being mostly modified to liair-scales. 

 The abdominal tergitcs are sjiinose all over, the spines as stout as in Amorplin, le^s 

 weak than in Sphinx. Anterior tibia ending in a heavy thorn, homologons to 

 that of Sphinx ocdlnta, ccrisi/i, and kindcrmanni. Frennlnra vestigial in lioth 

 sexes. 



S. Tenth abdominal sternite broader than in Sphin.r. C'lasper very broad, 

 very obtnse, the end of the abdomen apjiearing trnncate ; har^ie with two distal 

 lobes corresponding to those of Amorpha, and an upper dentate ridge. Penis- 

 sheath withont external armature ; a conical tooth n])on the membrane of the dnct 

 inside the sheath. No retinaculnui. 



? . Vaginal plate with a low thick ridge before the vaginal cavity, witliont 

 lobes ; the whole eighth segment strongly ohitinised. 



Larva graniilosp ; head more triangnlar in the last and in the first stages 

 than in the intermediate ones ; horn very short, longer in tlie yonng larva ; 

 thoracic tergitcs transversely raised, the crest also more prominent in the younger 

 caterjtillar. — Food-plants: Populus; Salix. 



Pnpa similar to those of Amorpha and Sphinx. 



Hah. Nearctic Region, from C!anada to Mexico, westward to the Pacific. 



Only one species, which is individually, seasonally, and geographically variable. 

 Bntler put this insect (in 1877) into a genus comprising the Old World species 

 allied to dyras, and maintained that " this is unquestionably the proper place for this 

 species." Grote accepted Butler's opinion as being well founded ; and since then 

 numerous writers have followed in the same wake. However, the affinity of 

 modesta with dyraa and allies is very distant. Apart from structure, which was not 

 known to Bntler and (Jrote, and most likely not to any of the authors who were 

 misled by them, and therefore may be passed over, any casual oliserver who is 

 ac(|uainted with the various sjiecies of Sphinx, Amorpha, and Butler's Triplorjon 

 (called by Moore Marumha, and dealt with in this Revision nnder tliat name) can 

 scarcely fail to notice the close agreement in colour and pattern between Pachy- 

 Kphitix, Sp/'in.r, and Amor/iha, and the consjiicuous dissimilarity of Afarnmha, the 

 species of which have all, on the forewing, the peculiarly curved, almost loo])ed, 

 discnl lines. 



Pachyxphinx is to a certain extent a combination of Amnrph i and Sphinx. 

 The thorax is unicolorous (or practically so) as in Amorpha ; the hindwing is red as 

 in SphinJ', and has the same anal jiatch as Sphin.r liindermanni ; the forewing 

 agrees decidedly better with that of Amorpha. There are on the forewing of 

 Amorpha, in the middle area, five lines : two between the base of M' and the end 

 of the cell, the more proximal line forming the border of the dark band, the second 

 line being situated within the band and disaj)])earing often; beyond the cell there 

 are three more lines, the first obscure, often absent, the second more or less crenate 



