84 



THE ENTOMOLOGIST. 



wings rather large and of peculiar form, 4| mm, long by l£mm. 

 wide ; the greatest width is near the tip, and they are again 

 broader near the base, so that the hind margin is broadly 

 emarginate. I have examined a male and a female taken at 

 Hammersmith fifty years ago. The wings are very slightly 

 larger in the female. A male taken recently at Brockenhurst 

 agrees with the Hammersmith male, except that the wings are 

 slightly shorter, and not so distinctly lobed near the tip. 



14. P. (Omaseus) nigritus, F. — Fully winged. Wings, 

 7-10£ mm. long by 3§-4£mm. wide ; elytra, 5£-6| mm. long. 



In this common species the wings vary a good deal in expanse. 

 There is also considerable difference in the size of the indi- 

 viduals, but this difference is exaggerated in the wings. The 

 specimens from the Scotch mountains are probably the form 

 found in Switzerland and called rhceticus by Heer (cf. Schaum, 

 Ins. Deutschl. i. 458) ; they are considerably smaller than the 

 type, and in five specimens I have examined the wings are uni- 

 formly reduced to the minimum mentioned. This depauperated 

 form is not, however, confined to the hill regions, as Commander 

 Walker has sent me a specimen, taken at Oxford, which scarcely 

 differs from the hill individuals in size and in the wings. 



It should be noted that, though the wings differ considerably 

 in expanse, they are all of normal shape, and apparently there is 

 no tendency to assume the peculiar shape of the functionless 

 wings of P. anthracinus. 



I have examined eighteen examples, five of them from the 

 Scottish hills. 



15. P. (Omaseus) gracilis, Dej. — Fully winged. Wings, 9 mm. 

 by 3£ mm. ; elytra, 5 mm. I have examined two individuals, 

 both males (Wicken, Donisthorpe, April 22nd, 1910, and New 

 Forest, May 29th, 1909). The wings are remarkably ample. 



16. P. (Omaseus) minor, Gyll. — Dimorphic ; either fully 

 winged or with functionless wings, there being a great gap be- 

 tween the two forms, the wings being in one case about 6 mm. 

 by 2£ mm., and in the other case about 3 mm. by 1J mm. I 

 have examined sixty specimens of this interesting case, and the 

 numbers of the two forms are about equal. Probably the fully 

 winged form is really the more abundant, as I wished to see a 

 good many of the reduced form, and exercised some selection to 

 facilitate this. Considering, first, the fully winged condition : 

 the largest wing is quite 6i mm. long, and the smallest 5g- mm., 

 the length of elytra being about 5 mm. by 4 mm. respectively. 

 The wings are of the usual pointed form, and the nervures are 

 well developed and dark, except that in immature examples there 

 is but little pigmentation. 



The reduced form has a rounded-truncate apex of the wing, 

 and the organ does not extend beyond the stigma, the apical 



