AMERICAN NEUROPTERA. 125 



that in each of the teeth are inserted three small spimiles, de- 

 creasing in size externally. Fhijllomacromla sp. ? (Pi. VI, Fig. 

 5 c?) shows the teeth more strongly developed, the two upper- 

 most ones sharply pointed, while the spinules inserted in the 

 lower three are more numerous. The border of the ligula (PI. VI, 

 Fig. 5/) is thickly covered with hairs, and is flatter than that of 

 Perithemis. The lateral lobe of Mesothemis simplicicollis (PI. VI, 

 Fig. 5 g) resembles Tetragoneuria, although the teeth are obsolete 

 and the number of setse is greater. The ligula is like that of Peri- 

 themis in shape but more prominent, and is heavily bordered with 

 hairs (PI. VI, Fig. 5 a). Epophthalmia'elegans is very different from 

 the others of the group. Tiie lateral lol)e (PI. VI, Fig. 5 c) is bor- 

 dered with long, sharp, strongly incurved teeth, seven in number, 

 and the setae are entirely absent; while the ligula (PI. VI, Fig. 5 b) 

 has a deep cleft in the center, with a rounded protuberance on 

 either side. The ligula of Orthetrum cancellatum (PI. VI, Fig. 5 e) 

 exhibits another variation ; a slight elevation marks the center, 

 while on either side are a number of small teeth with a small 

 spinule between each pair. 



The typical ^Eschninaj labium is well represented by Basioischna 

 Janata (PI. VI, Fig. '2,). The ligula shows a shallow cleft, and its 

 borders are thickly covered with hairs. The lateral lobes have a 

 strong, sharply pointed, ni(wal)le hook, while the end hook, although 

 short, is stout and sharp. The inner edge of the lateral lobe bears 

 a number of small chitinized spots, the witnesses of the existence of 

 teeth in that position earlier in the nymphal life. ^■Eschua constricta 

 (PL VI, Fig. 2 a) shows a different type of end hook, — blunt, and 

 straight across the end, with a small hook at the inner angle. In 

 the lateral lobe of Staurophlebia reticulata (PI. VI, Fig. 2 i) no 

 traces of teeth are visible on the inner edge, and the end hook is 

 short, but strongly incurved. The ligula of this specimen (PI. VI, 

 Fig. 2 c) has one very peculiar feature, — on either side of the central 

 cleft is developed a long and slender spine. The border external to 

 the spines is covered with short hair. The ligula of Boijera vinom 

 (PI. VI, Fig. 2 d) is characterized by a very small tooth on either 

 side of the central cleft and at some distance from it. The border, 

 on both sides of the teeth, is covered with hairs. 



TRANS. AM. ENT. SOC. XXX. MAY. 1904. 



