188 



Psyche 



[December 



The third, or Noctuid type, is perhaps the most interesting of all, 

 being at once the most complex, and that occurring in the largest 

 family. (Fig. 3.) Here there is no simple rounded bulla, either 

 subdorsal or subventral, but the whole spiracular region is deeply 

 excavated, the excavation including the posterior region of the 

 thorax as well. This cavity in the more typical case is roofed over 

 by the alula of the hind wing, which is largely developed, especially 

 in such Quadrifidffi as Catocala and the Euteliinse, and is enclosed 

 behind by a large flap, developed behind the spiracle. It seems to 

 be the same pleurite that has formed this and the bullae of the 

 Arctioids, but the development has been behind, not above the 

 spiracle, and is of a wholly different character, as the figure shows. 

 Another interesting development is a deep fovea in the parapleural 

 region of the thorax, across which the suture between postscutel- 

 lum and epimeron may sometimes be traced. In this series the 

 epimeron, often heavily chitinized, tends strongly to break up, 

 and to develop more complex sculpturing, as is notable in Cato- 

 cala. Alypia and the Notodontidse (Fig. 5) show interesting 

 variants of this type. In the latter the lateral cavity is present, 

 but slightly developed, and the alula is rudimentary, not covering 



it, the lateral flap behind the spira- 

 cle is also absent, though the material 

 from which it forms is indicated as 

 a chitinized area about the spiracle 

 that already tends to overgrow the 

 lateral groove. The parapleural fovea 

 is well marked, however, and already 

 undercuts a portion of the para- 

 pleura, which makes a stiff and solid 

 connection with the abdomen (partly 

 broken in the figure). This type 

 could well represent the point of 

 origin of the Noctuid one, but is 

 wholly unlike the simple structure of 

 Apatelodes. In Alypia (Fig. 4) we 

 have a second rather simple modifi- 

 cation. The parapleural fovea is well 

 marked, but the region about the 

 spiracle is reduced, without any spe- 



Fig. 5 

 ministra 



Same view of Datana 



