534 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



Tertiary shales of Florissant, and is remarkable for the markings of the 

 tegmina, which are covered throughout (with the possible exception of 

 the anal area and the extreme base of the wing, which are obscure) 

 with minute, circular, equidistant pale spots, situated between the 

 nervules ; they have a mean diameter of half a millimeter, and a mean 

 distance apart of one and a half millimeters. The head is full and regu- 

 larly rounded, on a side view, with no prominences. The antennae 

 appear to have the usual structure, but the second joint is small, and 

 the thickness of the joints above the front of the prothorax is 0.45'"™, 

 already diminishing to O.S™''^ at the posterior border of the same; they 

 are broken shortly beyond this point, so that their length cannot be 

 determined. The mean diameter of the eyes is scarcely more than one- 

 third the shortest length of the gense. The costal margin of the teg- 

 mina is gently convex, with a regular curve throughout, or until close 

 to the tip; the inner margin has a similar though slighter convexity; 

 the principal branch of the externo-median vein passes through the mid- 

 dle of the wing. The legs are all slender, the hind femora very slight, 

 but little incrassated toward the base, the hind tibiae slender, equal 

 throughout, armed at tip with a pair of small, moderately stout, black- 

 tipped spurs, the hind tarsi about two-fifths the length of the tibise, the 

 <}law very slight. OviiDositor broad, gently curved, at least as long as 

 the hind tibiae, of nearly equal size upon the part preserved. 



Length of body (excluding ovipositor) 37"'"; depth of head 12.5"™; 

 larger diameter of eye 1.85"™, shorter 1.35"""; distance from lower 

 edge of eye to upper edge of mandibles d"""" ; length of preserved part 

 of tegmina 45.5""", probable length of. same 55""; distance from base 

 of tegmina to front of head 13"", from same to base of principal branch 

 of externo-median vein 14.5""; breadth of tegmina in the middle 16"™; 

 length of femora* 9"'"; middle femora* 10""; hind femora 19"™; 

 fore tibiae 9.5""; middle tibiae 10.5""; hind tibiae 21""; fore tarsi 

 7""; hind tarsi 8""; apical spurs of hind tibiae 1.75""; claw of hind 

 tarsi 0.9"" ; greatest breadth of hind femora 3"™ ; length of ovipositor 

 (broken) 18"", breadth at base 3"", at a distance of 14"" from base 

 2.35"". 



The specimen (No. 11,557) was found at Florissant by Mrs. Charlotte 

 Hill, and is preserved on a side view, with the left (upper) tegmen and 

 the ovipositor drooping, the other parts in a natural attitude, the legs 

 drooping. 



Neuroptera: Dysagrion (5us, Agrion — nom. gen.). 



This new type of Agrionina belongs to the legion Podagrion as de- 

 fined by Selys-Longchamj)s, having a normal pterostigma, much longer 

 than broad, the median sector arising from the principal vein near the 

 nodus, the subnodal a little further out, the quadrilateral nearly regular 

 and longer than broad, and many interposed supplementary sectors. 



* There ia some doubt about these measurements, the basal portions being obscure. 



