lit mmim\ llittomolaflbt 



Vol. XL. 



LONDON, OCTOBER, 1908. 



No. 10. 



FOSSIL OSMYLID.4^. (NEUROPTERA) IN AMERICA. 



BY T. D. A. COCKERELL, BOULDER, COLORADO. 



The Hemerobiida?, as understood by most authors, are divided by 



Handlinsch into several families : Dilaridas, Osmylidae, Polystoechotidse, 



Sisyrid?e, Nymphesidie, and Hemerobiid?e. Of these, the Hemerobiidae 



proper are abundantly represented in the North American fauna ; while 



(according to Banks, as shown by his recent Catalogue) we have two 



species of Polystoechotes^ one each of Sisyra and Climacia (Sisyridas), and 



one of Dilar. The Osmylidfe are not represented. In the Miocene shales 



of Florissant we find instead one Polystoechotes, two Osmylidce, and no 



Hemerobiidae, Sisyridae or Dilaridae. Probably not much importance should 



be attached to the apparent absence of several groups, but the existence of 



Osmylidse, an Old World group, is significant, and in harmony with other 



facts, such as the occurrence of a species of Nemopteridae in the shales> 



Scudder described one of the Florissant Osmylids as Osmyhis 

 requietus. He prefaced his account (Tertiary Insects, p. 162) with the 

 following remarks : The species we have placed here agrees somewhat 

 closely with the species from amber, Osm. pictus, referred by Hager to 

 this genus, but differs from it in its lack of any diverse colouring in the 

 wing>, as well as in some minor points of the neuration, as in the distance 

 of the outer series of gradate veinlets from the outer border of the wing, 

 their regular connection with one of the basal branches of the radius, the 

 regularity of the inner series of gradate veinlets, as well as the structure of 

 the cubital region. The two Tertiary species, however, agree together, and 

 disagree with the living types in the simple character of the costal 

 nervules, the much smaller number of sectors, and the character of the 

 basal half of the wing, where the sectoiial interspaces are regular and 

 broken by few and irregularly scattered cross-veins, instead of being so 

 numerously supplied as to break up the field into an almost uniform and 

 minute reticulation. The two fossil species would therefore appear to 

 form a section apart. 



