1882.] 



131 



Abdomen blackish to end of 6th segment, with testaceous lateral longitudinal 



lines ; third dorsal segment narrowly 

 testaceous on its posterior margin, 

 which, in its middle, is produced into 

 a very large, rounded, testaceous hump 

 clothed with black hairs, and extending 

 over a portion of the succeeding seg- 

 ment, in a cavity in which it fits ; 7th 

 to 9th segments wholly testaceous, 

 formed as in P.germanica ; appendages 

 of the 9th (the cheliferous) segment 

 elongate, band-shaped, not much di- 

 lated to the tips, which are regularly 

 rounded (not truncate), the colour 



testaceous, with blackish hairs, which 

 are more numerous at the tips. 



Wings broad, broadly-elliptical at the apex, vitreous with fuscous neuration ; 

 pterostigma pale yellowish. Marking apparently variable. In the $ from Finland 

 the only markings are short fuscous transverse spots on the anterior margin (whereof 

 two on the pterostigma are the most prominent), some apical spots, and a slight 

 clouding on some of the transverse nervules. In the $ from CEsel there is an ab- 

 breviated maculose transverse fascia towards the base, succeeded by a median elongate 

 costal spot, which is followed by a sub-apical, angulose, narrow, complete fascia ; 

 there are also apical spots and some clouding of the nervules. (The ? is not now 

 before me ; according to memory the dark fasciae were more distinct, and the apex 

 had a band broken up by pale spots, which were enclosed in it). 



Expanse, <? , 29 — 31 mm. ; ? , 34 mm. 



Island of (Esel {NolcJcen, 1 (^ ) ; Finland (Carelia, Appellerg, 1 ^ , 

 in the Ilelsingfors Museum) ; Saxony (Dretschen, Bostock, 1 ? ). 



Equal to large typical specimens of P. communis (excluding P. 

 vulgaris, Imh.) in size, but structurally allied to P. germanica, with 

 which it agrees in the comparative length of the four modified termi- 

 nal segments, and also, to some extent, in the nature of the wing- 

 markings. It differs especially from germanica in the more produced 

 hump on the posterior margin of the third dorsal segment, and in the 

 form of the appendages on the cheliferous segment, which, in germanica, 

 are shorter, more flattened, and with the apex truncate and more 

 dilated. This latter character is conclusiye (and there are also dif- 

 ferences in the parts underlying these appendages, but not easily 

 definable without dissection). The same characters will separate it 

 from the South European P. gibherosa, but in this latter, the hump on 

 the third dorsal segment approaches that seen in hyhrida. 



It is possible that P. hyhrida is peculiar to Northern Europe, and 



