532 Mr. D. Sharp and Mr. F. j\Iuir on the Comparative 



and sliglitly curved, the bases meeting on dorsal and ventral sides. 

 Basal-piece, forming a large sclerite on ventral face, with its edges 

 turned up along sides and base, meeting together where lateral 

 lobes are articulated. Internal sac undifferentiated. 



In the genus Parnns the lateral and median lobes are very small, 

 the basal-piece large, and forming a long chitinous and slightly 

 curved tube. The internal sac undifferentiated. Figs. 127 and 

 127« PI. LXIII, are of P. luridas. It has a curved chitinous 

 spine (c) on the ventral aspect of the median orifice. 



Family DERODONTIDAE. 



Form examined: Laricohius erichsoni Ros., Macugnaga. 

 Fig. 128 PI. LXIII. 



Laricohms erichsoni (PI. LXIII fig. 128). 



Trilobe form. Median lobe large, fairly wide, and pointed at tip, 

 formed of a large chitinous sclerite on dorsal aspect, membranous on 

 ventral face; median orifice on ventral aspect before tip. Lateral 

 lobes large, round at tips, excavate at base on inner side where 

 they envelop the base of the median lobe. Basal-piece large, foi'med 

 by a shield shape sclerite on ventral aspect, emarginate at base, and 

 membranous on dorsal face. Internal sac undift'erentiated. Closely 

 allied to Mycetuphagns q.v. 



Family CIOIDAE. 



Forms examined: Cis holeti L. and C. nitidus Herbst. 

 England. 



Figs. 129 and 129a PI. LXIII. 



Cis holeti (PI. LXIII figs. 129, 129a). 



Median lobe long, slender and tubular, with median orifice at 

 apex. Lateral lobes of tegmen forming a large plate on the ventral 

 aspect, turned up along the lateral edges, and the distal end flattened 

 and slightly expanded, forming a median, emarginated process and 

 a rounded process on each side of it ; basal-piece small, chitinous 

 on the ventral aspect. Internal sac not dissected out, but apparently 

 not diflerentiated. 



G. nitidus is on the same plan, but the large plate formed by the 

 tegmen is cleft down the distal half. 



The ventral aspect of the tegmen is an important 

 feature of this family. 



