ART. 23. BLISTER BEETLE TRIORANIA PARKER AND ROVING. 27 



Legs, represented by three pairs of low, broad, poorly segmented 

 tubercles. 



Spiracles, dcrso-lateral ; the mesothoracic and first seven abdomi- 

 nal ones somewhat salient and cupuliform, all alike and of medium 

 size; the metathoracic and eighth abdominal spiracles present but 

 minute. 



Differentiating characters. — The fifth instar is found in the same 

 comparatively large number of genera of the subfamily Nemogna- 

 fhinae as is the fourth. In all of these the instar is completely en- 

 veloped by the unbroken exuvium of fourth instar, but the shape of 

 the body and the texture of the surface is somewhat variable. 



In Hornia minutipennis Riley, the instar is curved, subovate, with 

 distinct segmentation, shining, thin skinned, rather soft and gradu- 

 ally becoming shrunken and almost triangular prismatic; however, 

 it recovers its original swollen shape before the transformation into 

 the next stage. Mouth parts and legs less reduced than in Tricrania, 

 Stenoria {analis Schaum), and most others. 



In Stenoria., Apaliis., and Sitaris the instar is straight, ovoid, with 

 shining skin; in Stenoria rigid and never deformed, in Apalus and 

 Sitaris soft and periodically triangular prismatic as in Hornia. 



In Zonitis and Nemognatha the larva is curved, almost regularly 

 cylindrical with bluntly rounded ends, rigid and, seen from the side, 

 velutinous due to the development of short hairs on the finely sha- 

 greened skin ; body opaque. Skin of sixth instar in these two genera 

 adherent to the inside of the skin of the fifth. In Sitarohrachys, 

 which possibly belongs near Zonitis. the surface is shining as in 

 Stenoria. 



All N emognathinae have one pair of mesothoracic and seven pairs 

 of abdominal spiracles, all well developed, of medium size or larger ; 

 the eighth pair of abdominal spiracles vestigial ; the comparative size 

 both of the normal and vestigial spiracles somewhat varying accord- 

 ing to the different genera; thus the normal spiracles are smaller in 

 Tricrania than in Hornia {minutipennis) but in both much smaller 

 than in Stenoria {analis) ; on the contrary the vestigial eighth ab- 

 dominal pair is smaller in Stenoria than in the two other genera. 



SIXTH LARVAL INSTAR. 



Figs. 12, 19, 20, 32, 35. 



Sixth instar inclosed in, but not adherent to, the unbroken and 

 not shed exuvia of the fifth and fourth instars. 



Length of larva, about 10.25 mm. Width, about 4.25 nun. 



Color, pale cream. 



Setae, few and short; body densely set with fine asperities. 



Body, ovate, ventrally slightly less convex than dorsally; eighth, 

 ninth, and tenth abdominal segments short, together forming an 



