| OCR Text |
Show 1892.] VARIATION IN SECONDARY SEXUAL CHARACTERS. 587 shall refer to these two forms as " high " and "low " males respectively. It appears that the high male is known from many places in Fig. 1- I. n. Forficula auricularia, the Common Earwig. I. Low male. II. High male. England and elsewhere, and that it was made into a distinct species by Stephens1 under the name F. forcipata. This species has not been retained by later authorities (see Fischer2 and Brunner von Wattenwyl3). After the visit to the Fames, the high males were found on the mainland near Bamborough in fair quantity, though not so abundant as on the Fames. W e have received also a large sample of Earwigs collected in a Cambridge garden, containing 163 males, of which 5 would come into the "high" class. A sample kindly collected for us by Dr. Norman, F.R.S., in his garden at Burnmoor, near Durham, contains no high male. The great abundance of high males at the Fames seems to be quite exceptional. With a view to determining the frequency of the high and low forms, 1000 of these Earwigs were collected for us by Miss A. Bateson on Sept. 12, 1892. The whole were taken in one day from three very small islands known as the Knocksies and Widerpern, which are joined to each other at low tide. Of the 1000 specimens 583 proved to be mature males. Before giving the results of the measurements, it is perhaps necessary to give the reasons upon which we believe these specimens to have been all adult. In thi3 matter we rely partly on the judgment of Dr. Sharp, F.R.S., who has most kindly assisted us in many ways throughout this investigation, and was so good as to take part in the work of measurement. W e are informed by Dr. Sharp that the full development of the elytra is only reached in the adult state in F. auricularia, and we have been careful to include no specimen having imperfect elytra. As may be seen in the figures, the development of the elytra in the high and low males is the same. Besides 1 ' British Entomologv,' 1835, vi. p. 6, pi. xxviii. fig. 4. 2 ' Ortboptera Europasa,' 1853, p. 74. 3 ' Prodr. d. europ. Orthop./ 1882, p. 12. |
