OF EXTBA-EUROPjEAN TaiCHOPTEBA. 123 



formed after the same plan. In both, the antenna of the female are 

 much shorter than those of the male, in humerali^ remarkably so. 

 Infmtimus these organs are slender througliout in the 6 , whereas 

 • m humerahs they are gradually incrassate in the apical portion. 

 A completely analogous formation of the eyes in both male and 

 lemale is to bo found in the micro-lepidopterous genus Adela. 



I have diagnosed and described this extraordinary genus anew, 

 because the description given by Mr. Walker is insufficient. It 

 appears to me that, having regard to the homologies of the 

 arrangement of the nervures in Trichoptera, an error has been 

 frequently committed, of which I have myself been guilty in 

 sonre previous descriptions in former papers. I allude especially 

 to the area or cell which has been called the "cellula thyridii " 

 m the anterior wing. To Kolenati we are indebted for a very 

 ucid explanation of the different veins, areas, and cellules ; and in 

 Ins index wmg (G-en. et sp. Trichop. pt. 1, tab. i. f. 1), taken from 

 Glyplot^lius, the "cellula thyridii " is the area between the two 

 veins which he terms "radii ramus thyrifer," and "radii ramus 

 elavahs, and which I have called (Trichop. Britannica) the " su- 

 perior and inferior branches of the ramus thyrifer." But in almost 

 all genera of Hydropsychidse, and in several genera of Lepto- 

 cendaj, e. g. Ascalaj)liomerus, Anisocentropus, Qamnema, Asoto- 

 cems, Galamoceras, Ileteroplcctron, &c., the superior branch of the 

 ramus thyrifer (- radii ramus thyrifer " of Kolenati) furcates near 

 the middle of the wing ; and this furcation is generally closed by a 

 transverse veinlet placed nearly on a level with that closing the 

 discoida cell, and forming a ceUule, which has been usually termed 

 the ceUula thyridii," though the true cellula that should be so 

 called equivalent to that in the Limnophilid^, &c., lies beneath it, 

 extending to near the base, and usuaUy ending soon after tlie 

 commencement of the ceUule formed by the connected ramules of 

 the superior branch. This latter cellule, then, I propose to call 

 the cellula medianar A reference to the outline figures of the 

 wings of any of the above-named genera will more fully explain 

 my meaning. ^ 



In Mr. Walker's description of the genus Ascalaphomerus the 

 words^ ceU of the thyridium " should then read "median cel- 



, '\, ^^?. ^'^ " iiiterclaval areolet " is in reality the true " eel- 

 lula thyridu." 



Heteboplectbon, gen. nov. 



Calcaria2,4,2, J; 2,4,4, $. Maris tibia> pxjsticc-e fimbriis 



9* 



