Vol. xxiii] ENTOMOLOGICAL NEWS 441 



Gyropus ovalis Nitzsch. 



Specimens of this species and of the following from the 

 guinea pig, Cavia cobaya, sent in by H. E. Ewing (Urbana, 

 111.). (Also from Cambridge, Mass., by S. S. Berry.) 



Gyropus gracilis Nitzsch. 

 Many specimens (Urbana, 111.; Cambridge, Mass.). 



Gyropus bicaudatus n. sp. (PI. XX, Fig. 3). 

 A large series of specimens taken by W. M. Mann from a 

 wild guinea pig (Cavia cutleri), collected by Dr. W. E. Castle 

 in Peru. This species closely resembles in general habit 

 Nitzsch's G. gracilis, but is strikingly different in the form of 

 the last abdominal segment in the male. In the present species 

 this segment narrows and gives rise to two prominent append- 

 ages, each bearing a strong spine, giving the insect a very 

 characteristic appearance. This difference is shown in Figs. 

 3b and 3c, the former being drawn from specimens of G. gra- 

 cilis Nitzsch. 



Description of male : Entire insect pale, often white or transparent. 

 Head closely resembling that of G. gracilis, Nitzsch. Antennal, ocu- 

 lar and temporal bands faint, continuous, marginal, enlarged slightly 

 around the lateral emarginations ; numerous minute hairs on the mar- 

 gin of the rounded clypeus and a row across on the surface near the 

 margin ; also several hairs on the divergent sides before the lateral 

 emarginations and on the convergent temples. Thorax narrower 

 than head, prothorax almost circular, with posterior margin slightly 

 angled on the meson ; metathorax quadrilateral, sides slightly round- 

 ed. Abdomen long and narrow with sides, between the second and 

 sixth segments, almost straight ; last two or three segments tapering, 

 the last being produced into two appendages (Figs. 3 and 3c), each 

 appendage bearing a stout spine; a short fine hair on the lateral mar- 

 gin of this segment just above the appendage. In old specimens a 

 faint transverse band is visible across each segment; a row of ex- 

 tremely minute spines or prickles across each segment. 



Measurements: $ 1.16; $ 1.22. Length Width 



Male Female Male Female 



Head 18 .18 .16 .18 



Prothorax 10 .10 .12 .14 



Metathorax 12 .12 .12 .14 



Abdomen 76 .82 .28 .36 



