306 TERTIAKY INSECTS OF NORTH AMERICA. 



pair of elongated subapical cells are formed between the radial and upper 

 ulnar veins by their union through a cross- vein shortly before the marginal 

 cross-vein ; considerably more than half-way from this first-mentioned 

 cross-vein to the apex of the wing cross-veins cut off the four apical cells. 

 The hind wings show in their upper half two forked veins united by a cross- 

 vein opposite the middle of the cells thus formed, and the lower, similarly, 

 to the simple vein which follows it. 



The large size of the insect and its relatively small head make it some- 

 what doubtful whether it should be retained in Agallia. 



Length of body, 8.5""" ; tegmina, 5.5"™ ; hind femora, 2°'" ; hind tibia;, 

 3.5°"". 



In memory of the late lamented and talented geologist, Henry Carville 

 Lewis, of Pennsylvania. 



Florissant. Four specimens, Nos. 307, 8293 and 8725, 13582, and 

 from the Princeton Collection, Nos. 1.801 and 1.805. 



2. Agallia flaccida. 



PI. 19, Fig. 18. 



This species is closely allied to the last, differing principally in the 

 denser structure of the tegmina, in which the neuration less plainly appears, 

 and in the brevity and relative breadth of the apical cells. The shape of 

 the tegmina is the same, being nearlv equal throughout with broad apex, 

 in contrast to the more oval form of the succeeding species ; they are a lit- 

 tle more than three times as long as broad, and the central apical cells are 

 hardly half as long again as broad. 



Length of body, 7.25"""; breadth of thorax, 2.5'"°' ; length of tegmiira, 

 5.5°'"'; breadth, LGS"""; length of hind tibiae, 3"°'. 



Florissant, Colorado. Three specimens, Nos. 7858, 7979, 10168 



3. Agallia instabilis. 



PI. 21, Fig. 1. 



This is a stouter species than those which have preceded, with rela- 

 tively shorter tegmina. A single specimen is preserved, with one of the 

 tegmina expanded. The extremity of the abdomen has disappeared, no that 

 the length of the animal can not be determined, but its great breadth can be 

 seen by comparison with the width of tlie tegmina. The legs are slender. 



