NOTES ON THE WINGS OF COLEOPTERA. 85 



part of the wing being absent, and the stigma much reduced. 

 The nervuration of the basal part of the wing is normal, except 

 for the small size. The vestigial wings vary from about 2£- 

 3j mm. in length, and the width varies to a somewhat greater 

 degree. 



I see no reason for doubting that the two forms are really 

 one species, although the gap between them is so wide. Both 

 the vestigial wings and those fully developed vary somewhat in 

 size, and the one individual having the largest vestiges (about 

 3g- mm. long) is particularly interesting, because in it the wings 

 have not only developed in size beyond the stage of usual arrest, 

 but have also the beginning of the peculiar folding and creasing 

 that is so remarkable in the wings of Coleoptera. 



I have no evidence that the two forms are distributionally 

 isolated. P. minor is a very abundant insect in the South of 

 England, but in Scotland it beeomes rare. I have only sis 

 Scottish specimens, taken at different times at Thornhill about 

 forty years ago, and they are all of the short winged form. 



From Wicken Fen (Donisthorpe, April 22nd, 1910), I have 

 examined eleven specimens ; ten are of the fully winged form, 

 and one of the short winged. Chobham (Champion, May 14th, 

 1910), four specimens, two of each kind. Oxford (Walker, 

 November, 1909), four examples, three long winged, one short. 

 Freshwater, Isle of Wight, one with long, four with short wings. 

 In the New Forest the two forms seem to be about equally 

 common. 



It seems to be not improbable that the preponderance of 

 short winged forms in the Scottish fauna suggested by the above 

 may prove to be real. 



17. P. {Argutor) strenuus, Panz. — Flightless. The vestigial 

 wings varying from 1-2 mm. in length ; elytra, 4 mm. long. I 

 have examined twenty-five specimens. The great majority have 

 the vestigial wings just about 1 mm. long. Twenty-two speci- 

 mens are in this state, fifteen of them being from the New 

 Forest. Two examples have the vestiges about 1£ mm. long. 

 (Wicken, Donisthorpe, April 22nd, 1910 ; and Boar's Hill, Oxford, 

 Donisthorpe, April, 1910.) Only one individual has the wing 

 about 2 mm. long (Wicken, Donisthorpe, April 22nd, 1910). 



The size has possibly in this case something to do with 

 locality, as all the New Forest examples have the wings minute, 

 while the two examples from Wicken have them in one case 

 of the largest size, and in the other of the intermediate size. 

 Boar's Hill has yielded two specimens of small size, and one of 

 intermediate. 



18. P. (Argutor) diligens, Sturm. — Flightless. The vestigial 

 wings minute, |-f mm. long ; elytra, 3| mm. long. I have 

 examined thirty individuals, and find but little variation. The 

 localities range from the New Forest to Braemar. 



