BY K. .7. TILLYARD. 195 



new Suborder Paratrichoptera of the Order Tricboptera. But 

 tliis has been found to be quite incompatible with more recent 

 evidence forthcoming from a fine new fossil wing found in the 

 Upper Coal Measures of Newcastle, which I shall shortly deal 

 with in a separate paper. It is therefore necessary, in this 

 paper, to propose the recognition of a new Order Paratrichoptera 

 for the four genera of Trichopterous-like wings so far found at 

 Ipswich, and to explain carefully the essential differences between 

 the two types of venation found in the Tricboptera on the one 

 hand and the new Order on the other. 



Order MECOPTERA. 

 Family STEREOCHORISTID^E, fam.nov. 



Small Scorpion-flies having the radial sector four-branched, 

 the media six-branched. Cubital fork placed close to base; Cuj 

 united to M by an oblique vein, the posterior arculus (pa), which 

 appears to be itself a true branch of M; the vein formed b}- the 

 union of pa with Cuj continues as a straight, strong, convex vein 

 for some distance, and then stops suddenly short, dividing into 

 two weak and widely divergent branches, one joining up with 

 M 4 above, and the other with Cu. 2 +1A. below. Cu 2 fuses with 

 1 A not far from its origin. 



Originally I placed the genus Mesochorista in the family Pan- 

 orpidce. But its affinities are very great with the recent genus 

 Tazniochorista from Brisbane; and this genus, in its turn, is 

 allied to the better known genus Chorista. These genera, dis- 

 tinguished amongst other characters by the five- or six-branched 

 media of the forewings and the primitive form of the abdomen 

 in the male, most certainly deserve to be separated out from the 

 Panorpidoz as a separate family, Ghoristidce. I therefore now 

 propose to adopt this family, and to place the Triassic fossil 

 Mesochorista in it, together with the two recent genera Chorista 

 and Tamiochorista. The affinities of the Permian Permochorista 

 with the Choristidce are so close that it may also be advisable to 

 reduce the Permochorislidm to the status of a subfamily of the 

 same family. 



