June, igoi] 



PSYCHE. 



213 



teeth. In the front of each hxrge lat- 

 eral plate is a narrow dorso-ventral 

 sclerite carrying the jaws. These are 

 two in number on each side. The an- 

 terior one (the mandible) is large, strong, 

 toothed terminally, and provided on the 



inner side with a large, softer, movable 

 lobe. The posterior jaw (the maxilla) 

 is less chitinous than the other ; it is 

 flat and provided at its outer angle with 

 several papilla-like processes. 



GYNANDROMORPHISM IN A NEW SPECIES OF HILARA.* 



BY AXEL LEONARD MELANDER, AUSTIN, TEXAS. 



While collecting insects in Western 

 Wyoming during September, 1895, Dr. 

 Wm. M. Wheeler chanced upon a very 

 remarkable fly. This insect, Dilophus 

 tibialis Loew, was taken among sweep- 

 ings from the high grass along the bor- 

 ders of Hunter's Creek, at an altitude of 

 about 8000 feet. The specimen was 

 abnormal in the possession of an anten- 

 nary appendage arising from the right 

 fore coxa. Concerning this curious out- 

 growth Dr. Wheeler has already pub- 

 lished a full account. t 



With the same sweepings in which 

 the Dilophus was taken were numbers 

 of an undescribed species of Hilara^ 

 and among these was another abnormal 

 specimen. As cases of malformation are 

 rare, and especially so among insects, 

 possibly on account of the number of 

 ecdyses which these animals undergo, 

 the occurrence of another teratological 



♦(Contributions from the Zoological Laboratory of the 

 L^niversity of Texas. No. i8). 



t Archiv fuer Entwickelungsmechauik der Organismen. 

 in. Band, 2 Heft, 1896. 



fly in the same locality in which the 

 Dilophus was taken is of some interest. 

 The specimens collected were stored 

 away until recently, when I undertook 

 to study them in connection with the 

 other species of Hilara. 



Like most members of the genus 

 Hilara, the new species exhibits strik- 

 ing sexual dimorphism, that is, apart 

 from the peculiar hypopygial modifica- 

 tions, the first joint of the fore tarsi is 

 greatly enlarged in the male, while of 

 normal shape in the female. This char- 

 acter, which is well-nigh universal in 

 the genus, is, like other secondary sex- 

 ual characters, subject to considerable 

 variation in form and size among the 

 various species, and is therefore of tax- 

 onomic importance. 



On sorting the Wyoming specimens 

 with regard to the separation of the 

 sexes, an individual was disco\eied 

 which, so far as external characltrs .ue 

 concerned, is neither a male nor ;i 

 female. This specimen has the alxkm- 

 inal styles of the female, wlilc at the 



