HEMIPTERA—HOMOPTERA— APHIDES. 251 



Other members are absent. The parts which can be studied are thus very 

 similar to those found in Geranchon petrorum, described above, from the 

 same bed. Owing to the absence of the margin, the shape of tlie wing can 

 not be determined The postcostal vein is thick througliout, but broadens 

 apically ; the first and second oblique veins are both perfectly straight, 

 originating scarcely farther apart than the width of the postcostal vein and 

 diverging considerably. From the position in which the wings are preserved 

 (one front wing almost exactly covering the other, and the two inclosing 

 between them both hind wings, also almost exactly superimposed) the first 

 and second discoidal veins of the two front wings and the two oblique veins 

 of each hind wing form a medley of almost confluent lines, so that it is a 

 little difficult to determine to which of the four wings and to what part of 

 that wing each of the eight veins belongs ; regarding the veins of the hind 

 wings there may, therefore, be some eiTor in the statement to be made, but 

 there can be little doubt of the position and relation of the veins of the front 

 wing, which appears to lie uppermost. The cubital vein originates at a dis- 

 tance beyond the base of the second oblique barely greater than the distance 

 at which the latter is placed from the first ; it makes an angle with the post- 

 costal vein of less than forty-five degrees ; is nowhere in the least degree 

 sinuous, but is bent very slightly forward at each forking, rather more at 

 its first than at its second ; sends off its first branch at slightly less than a 

 millimeter from its base ; forms with it an angle of twenty-five degrees, and 

 at an equal distance farther on emits its second branch at a similar or slightly 

 smaller angle; both the branches are j>erfectly straight, and the upper branch 

 of the last fork lies midway between the lower brancli and the stigmatic 

 vein ; the latter is similar to that of G. petrorum from the same beds, but is 

 not so strongly curved; the first branch of the cubital vein also divides 

 equally the space between the second oblique and the lower branch of the 

 last fork of the cubital vein. The oblique veins of the hind wing originate 

 at no greater distance apart than the first and second oblique veins of the 

 front wings, are a little less divergent than they, and equally straight. 



Lengtli of fragment of wing, 5"""; its probable complete length, 6™™; 

 breadth of same, 1.3.5°""; distance from base of front wing to the origin of 

 the stigmatic vein, 4.1""°. 



To this may be added, from specimens obtained at Florissant, that 

 the body is stout and plump and the hind femora as long as the breadth 



