244 PROCEEDINGS OF THE ACADEMY OP 



jointed ; and further he does not make any mention of the spines on the under 

 side of the joints, peculiar to the tf Arrhenica; 2d, by the wings, which, 

 according to Wiedemann, are like those of T i p u 1 a, where, as in Arrhe- 

 nica the neuration is like that of Li mn ophila, and the position of the 

 last externo-medial vein shows uninistakeably that this neuration belongs to 

 the type of the Tipuhe brevipalpes ; 3d, by the palpi, which, according to 

 Wiedemann have joints of almost equal length inMegistocera; this is not 

 the case in Arrhenica. 



Besides Wiedemann, Macquart and Westwood have described species of 

 Megistocera from different parts of the world. But there is disagreement 

 between these authors as to the characters of the genus, a disagreement which 

 makes one suspect that the species described by them might belong to different 

 genera, only having the extraordinary length of the antennae in common. 

 Thus, disagreeing with Wiedemann, Westwood (in the Ann. de la Soc. Ent. 

 de France, 1 835, p. 682, ) describes aM.dimidiata from New Holland, whose 

 $ has short antennae. The same is the case with Macquart's M. 1 i m b i p e n- 

 nis 9 (Dipt. Exotiques, Suppl. i. p. 17) ; moreover, accordiug to him, these 

 antennae are 13-jointed, and those of the r^ are described as finely pubescent on 

 the inside; the last joint of the palpi of the same species is said to be long and 

 flexible, in contradiction to Wiedemann's description of the palpi of Megis- 

 tocera. 



But these three authors seem to agree in one point, the neuration of the wings, 

 and in this point all the species described by them differ from the two spe- 

 cies of Arrhenica described below. The wings of the former species are 

 described and figured as being like those of T i p u 1 a ; the wings of the latter 

 are exactly like those of Limnophila. 



Besides Wiedemann's above quoted words, Macquart's figures of M. f us- 

 cana and limbipennis (in Dipt. Exot. Suppl. i. tab. ii. iii. iv.) show the 

 last externo-medial vein originating from the pobrachial areolet, a diftinctive cha- 

 racter of the neuration of the Tipulae longipalpes. Arrhenica does not 

 even show an approach to such a neuration. 



The name Arrhenica is given in allusion to the length of the antennae of 

 the (j% and the prevalence in this respect of this sex over the other. 



The two species described below may be easily distinguished thus : 



A petiolate areolet . . . . A.spinosa. 



No petiolate areolet . . : A. longicornis Wk. 



A. s p i n o s a. Alas areola petiolata instructor, infuscatae, stigmate oblongo, 

 obscure fusco ; thorax vittis quatuor distinctis, mediis approximatis ; long, tf 

 4J-5 ; J circa 9 lin. 



rf Head cinereous, tawny below and on the anterior side of the tubercle ; 

 labium and palpi black ; antennae more than twice as long as the body, black, 

 two basal joints tawny ; the first three joints reach a little beyond the base of 

 the wing ; the fourth is longer than the third, and each of the following joints 

 is longer than the preceding one ; the sixth is as long or longer than all the 

 others together. Thorax cinereous, clothed with a soft cinereous down ; prae- 

 scutum with four blackish stripes ; the intermediate pair approximated, 

 parallel, limited behind by the suture ; lateral stripes broader, abbreviated 

 before and extended over the scutum behind ; scutellum brownish cinereous ; 

 metathorax more or less dark brown ; pleurae with a hoary reflection on their 

 lower part ; halteres pale at the base, knob black ; coxae hoary, trochanters 

 and base of femora yellowish tawny ; femora and tibiae tawny with brown tips ; 

 tarsi brown. Abdomen greyish black ; lateral edges, especially beyond the 

 third segment, yellowish ; venter paler ; forceps tawny ; structure like fig. 30. 

 Wings infuscated ; subcostal area tawny ; stigma oblong, brown, situated be- 

 tween the mediastinal and stigmatical cross-veins and divided in two by the 

 subcostal vein ; subapical area about equal in length to the second radial ; 



[Aug. 



