KKi.Looo: scLERrrr';s of riiK head. 53 



Una; su' in fig. 3, Plate II, Pampliila Iconardiis; si/' in fig. 6, Plate 

 II, Actias lund). The aborted mandibles, where I have observed 

 them present among lej)idoptera, articulate or fuse with the genae (see 

 ///(/in fig. 2, Plate II, Frotoparcc Carolina; and /////in fig. 12, Plate II, 

 Hciiiaris thysbe). In archippits the mandibles are entirely wanting* 

 (see fig. 1 1, Plate 11). 



Epicranium. 



The dorsal aspect of the head of arc/iip/>iis and the middle upper 

 part of the hind aspect are composed of the epicranium, a sub- 

 oblongate sclerite with its bounding sutures largely obsolete (see 

 cp in figs. 9 and 11, Plate II). A short, broad tongue projects for- 

 ward between the antennae meeting the backward-projecting tongue 

 of the clypeus, and distinctly set off from it by the short transverse 

 suture extending from fossa to fossa. The epicranium presents a 

 tumid transverse space on the hind asi)ect of the head, ending in two 

 tumid whitish spots (in simply denuded specimens). The suture 

 between eiMcranium and occiput is fairly distinct. The epicranium 

 varies considerably in shape in lepidoptera; in Actias litna it is trian- 

 gular in outline and relatively small (see ep in fig. 6, Plate II). The 

 suture between it and tlie occiput is usually sub-obsolete, as in 

 Pampiiila Iconardiis (see ep in fig. 3, Plate II). In Hepialiis mon- 

 taiiiis and in other specimens examined a faint median longitudinal 

 line dividing the epicranium into two portions, or "epicranial plates," 

 can be seen. 



Occiput. 



In arc/iippiis the occiput is a small narrowly oval sclerite bounding 

 the upper margin of the occipital foramen (see oc in fig. 9, Plate 

 II). It is fairly distinct from the epicranium, which is perhaps not 

 usually the case among lepidoptera. It is some times a very narrow 

 transverse sclerite, as in Actias lima (see oc in fig. 6, Plate II); or 

 again it may be sub-triangular with rounding apex and base, as in 

 Protoparce Carolina (see oc in fig. i, Plate II). It is usually slightly 

 tumid in its central portion. 



Post-genae. 



This name may be ajjplied to two important sclerites, constituting 

 the posterior portions of the orbits of the eye's, and also the lateral 

 portions of the hind aspect of the head (see p-g in fig. 9, Plate II). 

 These sclerites are called post-genae by f Prof. J. H. Comstock and 

 correspond to the "tempera" of |Kirby and Spence, and to ^^les 



*I do uot believe that the minute projections at the base of the proboscis in archippus 

 and usually called mandibles, are such. (See " Labrum," postea.) 

 tComstock, J. H., MS. 

 ^Kirby and Spence, Introduction to Kutomology, vol. 3. p. 488. 1828. London, 



