ENTOMOLOGY 



as presently described, though it differs as regards the smaller details of 

 construction. 



Lepidoptera. In Lepidoptera, excepting Eriocephala, the labrum is 

 reduced (Fig. 53) and the mandibles are either rudimentary or absent 

 (Rhopolscera) . The two maxillae are represented by their galeae, 

 which form a conspicuous proboscis; the grooved inner faces of the galeae 

 (or laciniae, according to Kellogg) form the sucking tube, which opens 

 into the oesophagus. The labium is reduced, though the labial palpi 

 (Fig. 54) are well developed. The so- 

 called rudimentary mandibles of Anosia 

 and other forms have been shown by 

 Kellogg to be lateral projections oi the la- 

 brum (Fig. 53) and are known as pilifers. 



FIG. 53. Head of a sphingid moth, Pro- 

 toparce sexla. a, antenna; c, clypeus; e, eye; 

 I, labrum; m, mandible; p, pilifer; pr, proboscis. 



FIG. 54. Head of a butter- 

 fly, Vanessa, a, antennae; /, 

 labial palpus; p, proboscis. 



The exceptional structure of the mouth parts in the generalized 

 genus Eriocephala (Micropteryx) sheds much light on the morphology 

 of these organs in other Lepidoptera, as Walter and Kellogg have shown. 

 In this genus there are functional mandibles; the maxilla presents 

 palpus, galea, lacinia, stipes and cardo, though there is no proboscis; 

 the labium has well developed submentum, men turn and palpi; a 

 hypopharynx is present. 



The sucking apparatus, as described by Burgess, is essentially like 

 that of Diptera. Five muscles, originating at the skull and inserted 

 on the wall of a pharyngeal bulb, serve to dilate the bulb that it may 

 suck in fluids, while numerous circular muscles serve by contracting 

 successively to squeeze the contents of the bulb back into the stomach; 

 a hypopharyngeal valve prevents their return forward. 



