— 62 — 



Scutum. — The scutum is much the larger of the two, con- 

 stituting, in fact, about two-thirds of the whole thoracic dor- 

 sum. It appears to be irregularly oblong in shape, sloping 

 dorso-caudad from its cephalic margin. Its latero-cephalic 

 angles are covered by broad flat leaves or plates, the patagia 

 (see below). A slight longitudinal mesal ridge, fading 

 away cephalad, is to be noted. A laterad projecting angu- 

 lated swelling occurs on each ventro-lateral border about 

 one-third of the caudo-cephalic length of the sclerite from 

 the ventro-caudal corner. 



Scutcllum. — The scutcllum is a rather small, subquad- 

 rangular plate, just caudad of the scutum. A narrow pro- 

 cess projects cephalo-ventrad from each lateral angle of the 

 plate (the processes thus lying ventro-caudad of the ventro- 

 caudal angles of the scutum). 



Lateral aspect. — The insertions of the forewings set off 

 the pleura from the dorsum. The three sclerites of each 

 pleura are easily made out ; and in addition, the large, divided 

 coxa and a portion of the sternum which runs latero-cephalo- 

 dorsad to meet the episternum give the appearance of three 

 additional pleural sclerites. 



Episternum. — The episternum lies cephalad of the epimeron 

 and is roughly trapezoidal in outline. 



Epimeron. — The epimeron is very oddly shaped, being 

 rather hour-glass-like in form with its long axis in an ap- 

 proximately caudo-cephalic direction. The broad portions 

 of the hour-glass are exaggerated by projecting, horn-like 

 processes. The cephalo-ventrad-projecting horn lies be- 

 tween the coxa and the episternum. 



Parapteron. — The third pleural sclerite, the parapteron is 

 conspicuous because of its remarkable development into a 

 broad, flat lobe, overlying and protecting the costal inser- 

 tions of the forewing and to a considerable degree the dorso- 

 cephalic aspect of the mesothorax. This lobe is called the 

 patagium, by writers on the Lepidoptera. 



