28 



tine is nearly equilaterally triangular, while the metacoxa is nearly as bi"oad, 

 the trochantines of both segments being very short and small. 



Papitionidce, ( Vanessa atalanta, pi. 7, fig. 20,20a). — The entire thorax is 

 relatively shorter, more compressed, the tergal portion descending farther 



down the sides, the epimeral and epistornal pieces being much shorter than 

 in any of the moths, while the coxa 1 and trochantines collectively are full as 

 short as in the Sjihimxiild'. 



Tergum. — Blesoscutum long and narrow, not much wider than the 

 scutellum; the latter is very large, elevated, both ends much alike, the poste- 

 rior end being much produced, so that in outline each side is nearly of equal 

 length. The metathorax is more vertical than in the moth's; the scutum 

 is large, the two halves not quite touching. The scutellum is very small 

 and narrow, vertical instead of horizontal, as in the moths, subtriangular, very 

 short and linear. 



Pleurum. — Episternal and epimeral pieces very short; middle trochantine 

 short and broad, triangular; hind trochantine larger than the coxa', where in 

 the Sphingida it is much swollen. 



The prothorax, which is so slightly developed tergally, has not been de- 

 scribed in these notes, and the tergum has not been figured. This comparison 

 of the thorax in different groups confirms the relative standing of the fami- 

 lies as usually given. The Pyralids should stand below the Phalcenidee, and 

 the latter below the Nocluidoe. 



The Phalcenidee hold a middle position between the moths below them 

 and the Noctuidce, while the jEgerklaz and Sphingidcc have strong resem- 

 blances to the Papilionidce; the Bombycidic and Zi/ivnidcc being more closely 

 allied to each other than to any other groups. 



§ 6. ANATOMY OF THE MALE GENITAL ARMATURE. , 



These organs, as in other orders of insects, differ much in form even in 

 different species of the same genus, so that it is impossible to lay down any 

 characters applicable to the family generally. I will briefly describe some 

 forms in certain of the typical genera of the family. 



In Petrophora truncata (pi. 7, fig. 24, 24a, 24f), the parts are, on the 

 whole, more largely developed than in any other species of the family. The 

 supra-anal plate ( pi.) is large and broad, subtriangular or rather scutellate ; 

 considerably longer than broad, rounded at the apex, with the two halves 



