.AIEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



59 



The outer exterior edge ol' tlie tube forms a strongly chitiiious seiuicircle which, hecoiniug thinner, finally passes 

 into the delicate membranous hinder -n-all. Also anteriorly a delicate membrane ai)i>ears to cover the chitiuous 

 l)ortion. 



We have here in opposition to the vreak naked iindi-rlip represented by a triangular ehitinmis )ilate in otlier 

 Lepidoptera a true ligula formed by the coalescence of the inner lobes of the second niaxilhe into a tube, as in 

 many Hymenoptera. and with free external lobes which correspond to the jjaraglossa' of Hymenoptera. 



Walter lias also detected a paireil straetuie which he regards as the liypoi)haryiix. As he 

 states : 



A iiortiou of the inner surface of the tube-like ligula is covered by a furrow-like band which, close to tlie 

 inner side, is coalesced with it, and in position, shape, as well as its appendages or teeth on the edge, may l)e 

 regarded as nothing else than the hypopharynx. 



While he refers to Burgess's discovery of a hypopharynx in Duiidif^ arclnppii-s,hii.vemi\r]ist\\i\t 

 this organ iu the lower Micropteryginse (Eriocephalid;?) exhibits a great similaritj' to the relations 

 observable iu the lower insects, adding: 



The furrow is here within coalesced with the inner side of the labium, and though I see in the entire structure 

 of the head the inner edge of the ligula tube extended under the epipharynx as far as 

 the mandible, I must also accept the fact that here also the hypopharynx extends to the 

 mouth-opening as in all other sacking insects with a well-developed nnderlip, viz, the 

 Diptera and Hymenoptera. 



Another feature of importance diagnostic of this suborder is the 

 mandibles (fig. 3), which, in form, size, and the presence of teeth, are 

 closely related to those of the lower maudibulate orders, being, as Walter 

 states, in the form of true guawing jaws, like those of the biting insects. 

 They possess powerful chitinous teeth on the opposed cutting edge, twelve 

 to fifteeu on each mandible, and also the typical articulating hook-like 

 processes by which they are Joined to the gena, and fit in corresponding 

 cavities in the latter. In Micropteryx and other of the more generalized 

 moths the mandibles in a very reduced form have snrviveil as fnnctionless 

 vestiges of tlie condition in Eriocephala. 



Turning now to the head and trunk, we find other primitive characters 

 correlated with those just mentioned. 



Tlie head is of moderate size, as well as the body, with small comjjound 

 eyes, and with two ocelli. The occipital region is well developed, as is the 

 «picraiiium; the clypeus and labrum are of moderate size. 



The generalized nature of the thorax is especially noteworthy. The 

 prothorax is seen to be very much reduced, the two tergites being separate 

 and minute, not readily seen from above. The rest of the thorax is very 

 long, exhibiting but little concentration. 



The mesothorax is but slightly larger than the raetathorax. The mesoscutum is very short; 

 the scutellum rather triangular than scutellate. 



The metathorax is but little shorter and smaller than the mesothorax and i-emarkable for the 

 widely separated halves of the scutum, a neuropterous character (comjiare Ascalaphus and 

 Corydalus), in which it differs from ]\Iicr6pteryx. The shape of the scutellum is that of a low 

 flattened triangle. 



As regards the abdomen, attention should be called to the dispavity in size and shape between 

 the sexes; also to the male genital armature, which is very large and completely exserted, 

 and reminds us of that of Corydalus, in which, however, the lateral claspers are much reduced; 

 and also of that of certain Trichoptera (Sericostonia, Tinodes, Stenophylax, Hydropsyche, etc.). 

 The venation of both pairs of wings is much as in jMicropterys. 



The larval characters of this suborder it would be difiQcult to give, for in the remarkable larva 

 of Eriocephala calfhelhi, as described and figured in Dr. Chapman's elaborate account, we appear to 

 have a highly modified form, entirely unlike the simple apodous larva of Micfopteryx and perhaps 

 quite unlike the primitive stem-forms of lepidopterous larvre. Chapman well represents its form, as 

 ■we can testify from mounted specimens in a slide kindly given us by him. The body is broad 



Fig. 3. — Mandible of Erioce- 

 phala calthdUi; a. a', inner .ind 

 outer articulation; s. cavity of 

 the joint (acetabulum) ; A, end 

 seen from .side of tbe exulting 

 edj^e. — After Walter. 



