Deeonibei, 1915.] 321 



laterally by membranes of considerable extent ; the dorsal blade com- 

 mences as two fangs or roots, and behind these roots is gradually 

 narrowed to form at the apex a process of very different elongation, 

 accordiug to species, and often perfectly transparent and colourless 

 towards its exti-emity. The ventral blade, though hard (? chitinous), 

 is transparent (like thin glass), sometimes colourless, but in other 

 cases more or less pigmented ; it is shaped very differently from the 

 dorsal blade, being approximately parallel-sided, narrower in front 

 where it articulates (or is conlinuovis) with the roots of the dorsal 

 blade, which in P. marifinnis are largely dilated latero-ventrally ; near 

 its extremity it exhibits a stronger chitinisation, which is coloured and 

 tawny, and therefore appears to form a cross-piece. There is no 

 differentiated sac, the duct being traceable as a duct tO""ihe , orifice, 

 which lies just above the cross-piece. f^ ^ 



P. MARITIMUS Th. 



This is really a very distinct species. In addition to the peculiar 

 livid yellow colour of the upper surface, and the yellow palpi and head, 

 the aedeagus marks it off quite definitely from all the others I have 

 examined ; the dorsal lamina of the median lobe being prolonged at 

 the tip, and consisting of a coloured portion that extends beyond the 

 cross-piece abovit as far as the width of the latter, and a transparent 

 terminal or appendicular poi'tion of similar length. The laminar 

 dilation at the base of the fang is greater than in the other species. 

 The diagram gives a very fair idea of the strvicture in this species. 



Some caution is necessary in deciding as to the colour of the 

 clypeus and vertex in P. marifinivs ; the tegument being very trans- 

 parent, the dark colour of the underlying structures often obscures 

 the real paleness, and in addition to this the labrum is black in the 

 female, though yellow in the male. 



P. HAiiOPHiLus Bedel. 



We are indebted to Mr. Newbery for the identification of this 

 species, he having introduced it as new to Britain in the same 

 number of the Ent. Mo. Mag. that contained my notes on the genus 

 last year. The determination rests on an examination by Capt. Deville, 

 who is so careful and competent an entomologist that we may accept 

 it as correct, though I should not have arrived at the same conclusion 

 from the descriptions, the species being very different from the waW- 

 timuN with which Ganglliauer and others have confused it. 



A.\ 



