ABT. 23 A NEW FOSSIL INSECT CARPENTER 6 



Typtis Sellards, and Blegatypus Tillyard. Typus may be distin- 

 guished (Tillyard, 1925) by having R3 arising before the middle of 

 the wing; AC, a simple cross- vein situated obliquely between two 

 normal cross-veins; a single row of cellulose between lA and 2A; 

 and wings about ten centimeters long. In Megatypus^ R3 originates 

 bej'^ond the middle of the wing; AC is a strongly formed (concave), 

 oblique vein connecting Cuo with lA; there are two or more rows 

 of cellules between lA and 2A; and the wings are from 18 to 30 

 centimeters long. In the fossil from the Grand Canyon there are 

 no traces of cellules or of the anal crossing, but the absence of AC 

 suggests that this vein was only weakly developed, as in Typus^ and 

 not well developed, as in Megatyp'us. E.3 arises at least slightly 

 basally of the middle of the wing, which is 10.5 cm. long, so that 

 this species, although lacking many other features, may be placed 

 in the genus Typu^ with very little chance of error. 



Genus TYPUS Sellards 



Typus Sellards, Amer. Journ. Sci., ser. 4, vol. 22, pp. 249-258, 1906. — Tillyard, 

 Amer. Journ. Sci., ser. 5, vol. 10, pp. 41-62, 1925. 



TYPUS GILMOREI, new species 



Plate 1 



Described from a nearly complete, left forewing, viewed from 

 above, with the following characteristics : Wing narrow and elon- 

 gate, with a pointed apex, and a reduced anal area ; length of wing, 

 10.5 cm. ; greatest width, at the middle of the wing, 2.3 cm. ; width at 

 the base, 1.5 cm.; precostal area small; Sc (concave) long, extending 

 beyond the middle of the wing; R2 and R3 (both concave) apparently 

 diverging at a point just basal of the middle of the wing; Cuo (con- 

 cave) broadly undulated ; lA (convex) only slightly undulated. These 

 are the only characters which can be assigned to the species with 

 moderate certainty. The costal margin appears to have been 

 macerated away, so that its shape is a question, but one would assume 

 from the basal and apical portions that it was nearly straight. The 

 furrow of the subcosta can be traced indistinctly along this missing 

 area almost to the apex of the wing. The presence of this shallow 

 furrow, which can be seen in the photograph, supports the idea of 

 maceration, since it would indicate that although the front part of 

 the wing membrane was badly decomposed, the strong subcosta was 

 nevertheless able to make a faint impression in the sandy mud. 

 The R-j-M stem is very obscure at the base, appearing as an inter- 

 rupted and irregular series of projections. R^ (convex), and R2 

 and R3 (both concave) are plainly visible at the middle of the wing, 

 but the origin of the radial sector is very indistinct. The media 

 is so obscure as to be almost invisible, except at the base where there 

 is a suspicion of a convex ridge. Cuo (concave) is very distinct at 

 the base, but the remainder has been broken away. lA (convex) 



