SOME NOTES OX THK CLASSIFICATION OP EARWIOS. 07 



form of the tarsi. In two curious s^enera, Apachi/s and Ta<jalina, the 

 tarsi are curiously formed and very different from those of all other earwigs, 

 but, in the remaining groups, the 2nd tarsal segment is found in 

 two forms, either simple, cylindrical, and very small, characterising 

 one great group of genera, or else flattened and lobed, characterising 

 the other group of genera ; in Chdisorhes, it is not broadened but pro- 

 duced in a long slender lobe under the 3rd segment, while, in Forjicala 

 and the allied genera, it is dilated and heart-shaped. This is the only 

 generic character which I have found to be invariable. 



Another important point is the presence or absence of the lateral 

 fold-like tubercles on the 2nd and 3rd abdominal segments, which 

 appear to fulfil the function of stink-glands. Several allied genera 

 are distinguished from each other by the presence or absence of these 

 glands; for instance, they are present in Diplati/s but absent in 

 Ci/Undrofiaster; present, often remarkably developed, in Forcipida, but 

 absent in Lahidura ; present in Brarlnjlabis, but absent in Aniwlabu, 

 and Gonolabis ; present in Chaetospauia, Sparatta and Mecomera, but 

 absent in PlaUjlahia. Very often, in these cases, these tubercles are 

 large and noticeable, and there can be no doubt as to which genus the 

 insect belongs, but it often happens that they are very faint, 

 indistinct, and perhaps almost obsolete, in which case mistakes can be 

 very easily made, and indeed often are. 



The development of the organs of flight is notoriously an unstable 

 character in many groups of insects ; in Orthoptera and in earwigs this 

 is especially so. CarcinopJiom is merely a Psali^ without wings or an 

 Anisolahis with free elytra, and Xeolohupliora is practially the same as 

 Opibtliocosiuia, with no Avings and rudimentary elytra. 



From this it will be seen that it is very easy to range any species 

 of earwig in the wrong genus, and, as a matter of fact, the generic 

 position of several species depends purely upon the personal opinion of 

 the writer. 



The forceps, again, would appear to offer very good points of 

 distinction, but they are so extremely variable in size, shape and 

 development, that little weight can be placed upon them. Their 

 general appearance alone can have any importance, and very often 

 under-development will give an earwig the appearance of belonging 

 to an entirely different genus. Thus, the genera Anechura, Apteri/nida 

 and Forjinila, are distinguished almost entirely by i.he form of the 

 forceps of the male. If, therefore, one has only females to examine, 

 the generic position is purely a matter of guess-work ; nothing can be 

 more severely deprecated than the habit of describing single females 

 as new species, unless there be some particularly striking character. 

 Apterijgida japonica, de Bormans, has been placed at different times by 

 different authors in all three of these genera. Apk'nji/ida cirndata and 

 A. jaiiori have been moved to and fro in the genera ; in the latest work, de 

 Bormans' monograph in Tierreich, they are placed in Aptei-ipiida, but 

 doubtless before long they will be put back into Anechura. Fur/lcula 

 silana and F. apeiinbia are at present in Forjlciila, before long they will 

 very likely be restored to Apteripihla. This state of things must continue ; 

 the only way out of the difficulty would be to unite the three genera 

 into one, thus returning to Dohrn's arrangement. This again would 

 appear unnatural, for no one would be likely to consider that A)iechara 

 inetallua, Dohrn, Aptcnjtj'ida arachidU, Yersin, and Fur/uula t(»iii-<y 



