262 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



This species approaches the genus Mesoneura in the disposition of the recurrent 

 nervures in both pairs of wings, the second being almost interstitial with the 

 second transverse cubitus. This character apparently tends to vary, however, as 

 the vein is more nearly interstitial in one wing than in the other. 



It is a broad, stout species. 



Pteronus prodigus, sp. nov. > 



Sex ? Length about 7 mm., most of the head broken away. -<}olor dark, 

 varied with paler. The anterior part of the mesonotum and the prothorax are 

 yellowish, while the scutellum and metathorax are darker. The mesonotum has 

 an anterior triangular dark spot and dark lateral margins. Abdomen pale, 

 banded on each segment with fuscous. The bands of the first and second seg- 

 ments reach only half-way across ; the following grow wider to the sixth, and the 

 seventh is again narrower. Wings hyaline, the venation as in Pteronus. Humeral 

 field divided by a cross-vein opposite the base of the first discoidal cell. Marginal 

 cell long and lanceolate, not divided. First submarginal cell small, obliquely 

 rounded above, the first and second sections of the cubitus equal. Second sub- 



Fig. 3. — Pteronus prodigus Brues. Wings. 



marginal cell very long, over three times as long as the second section of the 

 cubitus, receiving the two recurrent nervures. Third submarginal cell distinctly 

 longer than high, and higher at the tip than at the base. Anal cell petiolate, its 

 petiole originating just basad to the lower end of the basal nervure. Hind wings 

 with the first discoidal and first submarginal cell separate. 



T yve . _No. 2038, Mus. Comp. Zool., Florissant, Col. (No. 14,071, S. H. 

 Scudder Coll.). It is in a fine state of preservation, showing both front and hind 

 wings, but lacking a part of the head. 



The venation in this species is exactly like that of recent species, and the 

 color markings are disposed with a similar tendency to those of P. ribesii Scop, 

 and P. mendicus Walsh, two common North American species of recent times. 



Serres in his Geognosie ('29) has referred a fossil species from Aix to this 

 genus, but it is very doubtfully a member of Pteronus, as the genus is at present 

 restricted. 



